The past, present and future of the UK’s relationship with the EU
Catherine Barnard Ian Bond Nick Butler Catherine Day Charles Grant
Peter Kellner Julian King David Lidington David Miliband
Nicolai von Ondarza Philip Rycroft Daniela Schwarzer John Springford Anton Spisak Nathalie Tocci
The Centre for European Reform is a think-tank devoted to making the European Union work better and strengthening its role in the world. The CER is pro-European but not uncritical.
We regard European integration as largely beneficial but recognise that in many respects the Union does not work well. We also think that the EU should take on more responsibilities globally, on issues ranging from climate change to security. The CER aims to promote an open, outwardlooking and effective European Union.
Through our meetings, seminars and conferences, we bring together people from the worlds of politics and business, as well as other opinion-formers. Most of our events are by invitation only and off the record, to ensure a high level of debate.
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The CER is an independent, private not-for-profit organisation with offices in London, Brussels and Berlin. We are not affiliated with any government, political party or European institution. Our work is funded by donations from the private sector.
Catherine Barnard is a professor of EU law and employment law at the University of Cambridge and a member of the CER advisory board.
Ian Bond is deputy director of the Centre for European Reform.
Nick Butler is an energy economist, a visiting professor at the Policy Institute at King’s College London, and the co-founder and former chair of the CER.
Catherine Day is a former secretary-general of the European Commission (2005-15) and a member of the CER’s advisory board.
Charles Grant is director of the Centre for European Reform.
Peter Kellner is a political analyst and a former president of the polling company YouGov.
Sir Julian King is a specialist partner at Flint Global, former European commissioner for the security union (2016–19), and a former British ambassador to France (2016). He is also chair of the CER’s advisory board.
Sir David Lidington is a former senior UK government minister (2010-19) and a member of the CER advisory board.
David Miliband is president and CEO of the International Rescue Committee, former UK foreign secretary (2007-10) and a member of the CER’s advisory board.
Nicolai von Ondarza is a political scientist and head of the EU/Europe research division at the German Institute for International and Security Affairs (SWP).
Philip Rycroft is former permanent secretary at the Department for Exiting the EU (201719) and second permanent secretary at the Cabinet Office (2015-17).
Daniela Schwarzer is a member of the executive board of Bertelsmann Stiftung.
Anton Spisak is assistant director of the Centre for European Reform.
John Springford is a non-resident associate fellow at the Centre for European Reform.
Nathalie Tocci is professor of practice at the Johns Hopkins University SAIS, a former special adviser to EU High Representatives for Foreign Affairs, and a member of the CER’s advisory board.
The past, present and future of the UK’s relationship with the EU
Catherine
Daniela
Charles
Anton Spisak on the decade that has reshaped Britain but left its place in Europe unsettled.
When David Cameron promised “a straight in-out referendum” on Britain’s membership of the EU in his 2013 Bloomberg speech, he said it would be “a time to settle the European question in British politics” once and for all. Three years later, on June 23rd 2016, the British people voted narrowly to leave the EU. It was a decision taken in a particular political moment: after the financial and eurozone crises, amidst anxiety over austerity politics and immigration, and against a backdrop of deepening public distrust in Westminster. Its consequences have outlasted the moment. Brexit has reshaped Britain’s economy, politics, constitution and place in Europe and the wider world.
This collection of short essays, written by our staff, members of our advisory board and friends of the CER, asks what leaving the EU means a decade after the divisive referendum – for Britain, for the EU and for the relationship between them. The answer is neither simple nor settled. Brexit has not produced the national renewal promised by its advocates. Nor has it caused a sudden rupture in Britain’s diplomatic and economic relationship with the EU. Its effects have been more cumulative, more structural and more difficult to reverse. They appear in the trade that has not happened, the investment that has not been made, the political attention that has been diverted from other issues, the constitutional tensions that have deepened, and the influence that Britain has lost as the rules-based world order has begun to fracture.
John Springford and I begin by looking at the economic costs. Brexit has not ruined the British economy, but it has lowered its growth path and reduced trade openness. Perhaps the most uncomfortable lesson is that, although the costs of separation have been substantial, recovering lost ground would require Britain to re-open difficult political debates about the meaning of sovereignty and the value of migration.
David Lidington, a former cabinet minister who took part in the Brexit negotiations, widens
the lens to British politics. He argues that Brexit absorbed a decade of ministerial and parliamentary time without addressing the grievances that helped produce it. The vote to leave channelled popular anger at economic insecurity, democratic disconnection and immigration into the referendum outcome, but it did not resolve those underlying pressures. If anything, it deepened public frustration by consuming political energy that might otherwise have been used to confront Britain’s more acute social and economic problems.
Philip Rycroft and Catherine Barnard then turn to the constitutional and legal consequences of Brexit. Rycroft, former permanent secretary at the Department for Exiting the EU, shows how Brexit made the UK union more fragile while also making its break-up more complicated. Scotland and Northern Ireland voted to remain, yet were taken out of the EU; Northern Ireland became the place where the contradictions of Brexit had to be managed on the ground. Barnard, a leading scholar of EU law, shows that the UK may have recovered some formal autonomy from Brussels, but Brexit has not ended its relationship with EU law. Any closer future relationship will require renewed forms of alignment to EU rules. Sovereignty, as Barnard shows, has proved less absolute than was promised.
Peter Kellner, a leading pollster, examines the changing public mood. British voters increasingly regard Brexit as a mistake. But regret is not the same as a desire to rejoin, especially if re-entry would come on different terms than those of the UK’s UK’s pre-2016 membership. The politics of Brexit have shifted, but they have not shifted far enough to revisit the fundamentals of Britain’s post-Brexit settlement.
The next essays turn to security, defence and energy. Julian King, former EU commissioner and chair of the CER’s board, shows how reduced security links since Brexit have made it harder to tackle terrorism and organised crime. Ian Bond, deputy director of the CER, argues that the external threats facing Britain and the EU have not diverged since 2016 – but being outside the room has reduced Britain’s institutional access and ability to work effectively with its European allies. Nick Butler, an energy expert and former chair of the CER, makes a similar argument on climate and energy co-operation: physical interdependence and shared climate goals create a powerful case for closer partnership, even with Britain outside the EU. The challenge, across all these areas, is not whether closer ties are desirable –it is how to bring Britain closer to an institution that is not accustomed to accommodating a large country on its doorstep, let alone a former member-state.
The wider European and global context has changed too. David Miliband, former British foreign secretary, argues that Brexit weakened Britain, Europe and the West at precisely the wrong time: before Trump, before Russia’s fullscale invasion of Ukraine, and before today’s more disorderly, transactional world had fully emerged. Nicolai von Ondarza, of the German Institute for International and Security Affairs, shows that, for the EU, Brexit became one crisis among many. It did not lead to disintegration, and the EU has proved more resilient than many expected, even as Britain’s absence has altered the balance of power within it.
The final essays look ahead. Nathalie Tocci, a leading Italian political scientist, warns that the
current ‘reset’ in relations may have reached its limits: not because it rests on wrong instincts, but because it lacks a clear political destination. Daniela Schwarzer, of the Bertelsmann Stiftung, argues for a more practical agenda focused on resilience and economic security as the starting point for a deeper partnership. Catherine Day, former secretary-general of the European Commission, supplies the necessary corrective to the British assumption that pragmatism alone can dissolve the asymmetry between a single country and a 27-member union. If Britain wants closer ties, Day argues, the EU will expect corresponding obligations; it will not weaken the logic of membership for the benefit of a country that chose to leave.
Charles Grant, director of the CER, closes by asking whether the immediate ‘reset’ in UK-EU relations can become something more than a modest exercise in repair. His essay cuts through easy optimism about closer ties: the EU has little incentive to offer Britain a bespoke deal, and Britain has not yet decided what it is prepared to accept in return. Without a clearer political choice, the closer relationship will remain out of reach.
The common thread running through these essays is that, a decade after the referendum that promised to settle Britain’s ‘European question’, that question is anything but settled. Brexit has changed its form, not made it disappear. The old Leave-Remain argument may have lost its political force, but the grievances and strategic dilemmas behind it have not gone away. British politicians still need to rebuild trust in democratic politics, revive growth in a stagnant economy, defend their country’s interests in a more hostile world and decide how much influence they are prepared to trade for autonomy. None of these issues can be answered by Europe alone. But none can be answered sensibly while treating Europe as peripheral in today’s political and policy debates.
Proponents of leaving the EU offered ‘control’ as the answer to those questions in 2016. But control is not an end in itself – it is only useful if it enlarges a country’s capacity to act.
The irrefutable lesson of the past ten years is that sovereignty is neither absolute nor costless. For a medium-sized economy next to a far larger market, it is constrained by geography, economic gravity and political necessity. Sovereignty is worth less when it is bought at the expense of economic uncertainty, political bandwidth and strategic influence.
A decade on, the task is not to replay the referendum, nor to pretend that the pre-2016 settlement can simply be restored. It is to accept that Britain has not yet settled what kind of European relationship it needs for the world it now inhabits. Britain’s long-term interest may ultimately lie in rejoining the EU. But in the current political climate, that debate would risk reigniting old divisions and diverting attention from the more immediate challenges facing the country. What is needed now is a more honest assessment of the choices that lie between the status quo and membership: where closer alignment with EU rules is worth
the trade-offs, where autonomy still matters, and whether Britain can accept greater mobility with EU countries. British political leaders need to show their European partners that London understands the price of a closer relationship, and is prepared to make a serious case for it.
The EU, too, must draw a lesson from the past decade. If it is serious about becoming a geopolitical actor, it has a strategic and long-term interest in bringing the UK closer, even if that requires greater institutional flexibility. Defining the contours of a different, more ambitious partnership will require genuine political leadership and imagination – in London, in Brussels and across European capitals. That, surely, is the task for the decade ahead.
Anton Spisak is assistant director of the Centre for European Reform and editor of the CER’s ’Ten years after the Brexit referendum’ essays collection.
John Springford and Anton Spisak on how much Brexit has cost the UK economy – and why the hardest trade-offs still lie ahead.
Brexit was, among other things, one of the starkest ‘natural experiments’ in modern economics. Britain chose to pull away from one of the world’s largest markets – a market on its doorstep, governed by rules it had helped to write, and into which its firms and supply chains had been deeply integrated for more than four decades. No other advanced economy has so deliberately made trade with its nearest and deepest trading partners more difficult.
Before the referendum, most economists expected Brexit to be costly. The only question was how large the damage would be and how quickly it would appear. A decade later, the answer is clear. Brexit did not produce a sudden economic shock, but it did something more insidious: it created a persistent drag on Britain’s growth path. The UK’s Office of Budget Responsibility estimated that Brexit would reduce UK trade openness by around 15 per cent in the long run, lowering potential productivity by around 4 per cent. More recent studies suggest that the damage may be larger – around a 6-8 per cent hit to GDP and a 3-4 per cent hit to productivity by 2025. Earlier ‘synthetic control’ estimates, conducted by the CER, also found substantial losses to UK GDP, trade and investment.
Estimating counterfactuals is always difficult, and it has been harder still because Brexit coincided with Covid, the energy shock following Russia’s invasion of Ukraine, high inflation and years of domestic policy churn. But the evidence points in one direction –towards a weaker growth and productivity path that has been shaped through three main channels of trade, investment and migration. The size of each effect can be debated, but the direction should not.
The most direct channel has been trade. The Trade and Co-operation Agreement avoided tariffs on most goods, but it did not preserve
the same frictionless access to the single market that Britain had once enjoyed. Firms now face customs declarations, ‘rules-oforigin’ requirements, veterinary certification, regulatory checks, product certification procedures and continuing uncertainty over future regulatory changes. In modern trade, these ‘non-tariff’ costs matter more than duties levied at the border.
“ Brexit did not produce a sudden economic shock, but it created a persistent drag on Britain’s growth path.”
Our own latest estimates show that Brexit has reduced UK exports to the EU by about 12 per cent and imports by about 16 per cent. Goods exports to the EU are now about 16 per cent lower than what they would have been had the UK stayed inside the EU; goods imports are 14 per cent lower. These trade losses are substantial, and they are consistent with business surveys showing around half of UK exporters and two-thirds of importers reporting considerable costs from Brexit-related friction.
One striking feature of Britain’s post-Brexit economic performance is that services trade has held up relatively well. Our estimates suggest that this is not evidence of a Brexit dividend. UK services exports to the EU are 7 per cent lower, and services imports 19 per cent lower, than they would have been had Britain
stayed in the single market. The strength of services exports reflects rising post-pandemic global demand for the kinds of services in which Britain has a comparative advantage – especially business services, such as law, accounting and consultancy.
Our analysis also shows that most of the trade loss appears to stem from leaving the single market, not the customs union. Leaving the customs union introduced cumbersome ‘rulesof-origin’ requirements and customs paperwork, but it was the departure from the single market that meant losing the regulatory recognition that underpins friction-free market access. Some barriers can be reduced through selective alignment with EU rules and sector-by-sector mutual recognition agreements. But unless the British government is willing to revisit the red lines around rejoining the single market, it cannot recover most of the economic losses.
Investment has been the hidden casualty of separation. Firm-level evidence found that UK investment was 12-18 per cent lower by 2025, reflecting years of uncertainty, contingency planning, supply-chain adjustment and management attention diverted from expansion to adaptation. Firms may not have left Britain en masse because of Brexit, but leaving the EU was enough for them to scale back their ambitions, or to decide that the UK was a less attractive base from which to serve the wider European market.
Migration is the third channel of Brexit costs – though here, the effects have so far been limited, and possibly positive. Brexit ended free movement, but Conservative governments replaced it with a more discretionary system. According to recent estimates, Brexit reduced the number of EU-origin employees by about 785,000 by 2024, but this was more than offset by a rise in non-EU workers. Overall, postBrexit migration rules led to an increase of foreign-born workers of about 207,000 – or roughly 0.6 per cent of the workforce. Whether that migration dividend lasts is uncertain, as successive governments have tightened the visa regime, and net migration is plunging.
The fiscal consequences follow from the economic ones. A smaller economy means a smaller tax base. If the OBR’s estimate of a 4 per cent productivity loss is correct, around £40 billion of the roughly £100 billion in tax rises during the 2019-24 parliament were needed because of Brexit. Covid, energy prices, weak public investment and years of poor productivity performance have all weighed on public finances, but Brexit has made every fiscal trade-off harder.
It is tempting to look for a single dramatic refutation of these facts: that the German economy has barely grown over the last decade, or that investment has been sluggish across many European economies. But that misses the point. The costs of leaving the EU have been cumulative and counterfactual. They appear in the trade that does not happen, the investment that is not made, the productivity that is foregone, the political time that is lost and the taxes that have to rise. Britain spent the better part of the last decade arguing about the terms of separation from its closest economic partner while the country stagnated.
Acknowledging these impacts was treated as politically dangerous until recently. There are signs of change, however. Keir Starmer has recently said that Brexit “damaged the British economy”, while Chancellor Rachel Reeves has argued that Britain should align with EU rules where it is in the national interest. These are sensible statements, and also overdue ones. But the question today is not whether Brexit has been costly, but rather how much of the cost Britain is still prepared to bear for the sake of regulatory autonomy it has often chosen not to use, and sovereignty that has not delivered the change that many British voters expected in June 2016.
Getting closer to the EU can recover some lost ground. Selective alignment can reduce frictions; a veterinary agreement can ease agrifood trade; mutual recognition and mobility arrangements can help firms and workers. But none of these options is without political trade-offs. A decade after the referendum, the
British economy has not been ruined because of Brexit, but leaving the EU has made Britain’s hard economic problems even harder. The costs of separation are the costs with which people and businesses in Britain now live.
John Springford is a non-resident associate fellow at the Centre for European Reform and Anton Spisak is assistant director of the Centre for European Reform.
David Lidington on how leaving the EU absorbed a decade of British politics without addressing the grievances behind it.
David Cameron was right about one thing. I remember the meeting in the run-up to the 2016 referendum when he warned that, if the British people voted to leave the EU, the government and parliament would spend the next five to ten years having to work through the consequences.
That prediction proved accurate. Brexit has consumed a vast amount of the finite time, energy and bandwidth of successive governments: from Cameron’s 2013 Bloomberg speech, in which he promised an in-out referendum, to the fraught departure negotiations of the May and Johnson governments, to Rishi Sunak’s negotiation of the Windsor Framework in 2023, and now the Starmer government’s efforts to reset Britain’s relationship with the EU.
British ministers and officials spent vast amounts of time and energy renegotiating the terms of EU membership; designing and legislating for the referendum; wrangling both with the European Commission and internally within British politics over the detail of, first, a Withdrawal Agreement and then a Trade and Co-operation Agreement; sorting out transitional arrangements; agreeing with the three devolved administrations how to handle the more than 150 areas of EU law to be transferred from the EU to the UK that also intersected with devolved responsibilities in Scotland, Wales and Northern Ireland; drafting and enacting new laws to transfer EU arrangements onto a domestic legal basis, and establishing new regulatory systems to replace those of the EU.
The time spent sorting out Brexit was the time and energy unavailable to address more acute economic and social challenges facing Britain: poor productivity, inadequate skills,
patchy infrastructure, a persistent difficulty of turning innovative technology and research into large and profitable businesses, and the pressures created by an ageing society and falling birth rate.
“ The time spent sorting out Brexit was the time and energy unavailable to address more acute economic and social challenges facing Britain.”
Leaving a bloc in which Britain had been a leading player for more than 40 years – and by far our most important global trading partner, with rules intertwined in domestic law – was bound to be complicated. But the difficulty was compounded by the lack of any agreement about what leaving should mean in practice.
The Leave campaign took a deliberate decision not to specify the kind of relationship it wanted Britain to have with the EU. This was a shrewd electoral tactic, enabling them to deflect criticism of any particular model for future relations. But it meant that, apart from the Cameron government’s 2016 paper outlining alternatives to membership, little preparation had been done in advance of the referendum about the strategic choices that followed a Leave vote.
Arguments about why Britain voted to leave continue to this day. Immigration certainly mattered, but so did a wider sense among
millions of voters that the current economic and political system was failing them and their families. Global competition and new technological change were squeezing living standards. The financial crash of 2008 deepened the pressure on families and fostered a widespread sense that the system was rigged against the interests of ordinary people. I remember knocking on doors during the Remain campaign, making the case for the benefits of the European market for growth and jobs, and getting the response from Leave voters that they didn’t see any of those benefits in their life or work.
It is easy to say that the Brexit vote and the subsequent controversies undermined support for the established political parties, and it is certainly true that the interminable negotiations over Brexit and the deadlock in both government and parliament deepened public disaffection and resentment. But the underlying social and economic tensions in Britain, as in other advanced democracies, predated the events of 2016-2021, and have festered even as Brexit has faded from the headlines.
As the 2016 referendum approached, Carl Bildt, the former prime minister of Sweden, said to me: “You must tell Mr Farage that he is part of a European phenomenon”. Across Europe, insurgent parties of the nationalist right have drawn voters plagued by economic anxiety and fearful about immigration. In the US, the same forces have found expression through a reinvented, Trumpian Republican Party rather than a new party altogether.
Brexit also exposed tensions within the coalition that supported it. Most of the leading Leave campaigners argued for economic reforms based on deregulation, open markets and a buccaneering approach to trade – an economic model often dubbed ‘Singapore-on-Thames’.
But that was not what most Leave voters wanted. Their preference was for economic interventionism, protection and the regulation of business for the public good. The tension between those conflicting approaches has added to public frustration.
So too did the contradictions over immigration policy. Having campaigned vigorously to “take back control” and end the free movement of EU citizens, the leading Leavers, confronted by the realities of government, gave priority to ensuring a sufficient supply of workers for key public services and the private sector, and in effect substituted large-scale immigration from the Commonwealth for free movement from the EU, resulting in a belief by many who had voted to leave the EU that they had been betrayed.
The referendum and its aftermath were a divisive and bitter period in British politics. Personal friendships were broken. In some families, supporters of the two sides – often divided along generational lines – stopped speaking to each other. There was an uptick in support for Scottish separation and Irish unity. Much of that bitterness has abated over the years – and indeed opinion polls now show about 60 per cent of voters say the country was wrong to leave.
But the resentment directed at political parties and institutions has not dimmed. Nor have the profound economic and social problems that have fed it. Political leaders in Britain, as in other democracies, have yet to find the language or the policies to inspire a renewed sense of hope. Until that leadership is forthcoming, the anger and disillusion will continue.
Sir David Lidington is a former senior UK government minister (2010-19) and a member of the CER advisory board.
Philip Rycroft on how Brexit strained the UK union while making its break-up harder.
When Scotland’s then first minister, Nicola Sturgeon, called for a second referendum on Scottish independence in March 2017, she claimed that Brexit was “a significant and material change in the circumstances that prevailed in 2014.” The Scots had voted by a margin of 62 per cent to remain in the EU. They should now be offered a choice: stay in a post-Brexit UK or seek independence with the possibility of rejoining the EU.
In those uncertain times, it seemed possible that Brexit would not only shake the EU but rock the foundations of the UK as well. Northern Ireland had also voted to remain, and the Irish border was emerging as a major obstacle to a smooth departure. Although Wales had voted to leave, its then first minister Carwyn Jones shared Sturgeon’s frustration at the UK government’s refusal to involve devolved administrations meaningfully in the Brexit negotiations – and to contemplate a softer Brexit that would have kept the UK in the single market.
Yet the feared disintegration of the union did not materialise. The UK government simply refused to agree to a second Scottish independence referendum. “Now is not the time,” said Theresa May. Nor did Edinburgh and Cardiff secure a meaningful role in the negotiations with the EU. Westminster pressed ahead with various pieces of Brexit-related legislation despite the refusal of consent by both devolved legislatures. The Sewel convention, recognised in statute, states that UK Parliament will “not normally” legislate on devolved matters without their agreement – and Brexit exposed its limits. To add insult to injury, the Internal Market Act of 2020 deepened the resentment by imposing a version of the UK internal market which was widely seen by the devolved governments as constraining their regulatory powers.
Northern Ireland, the only part of the UK that shared a land border with the EU, meanwhile became a pawn in the struggle of competing visions of Brexit. Supporters of a softer departure were willing to accept closer legislative alignment with the EU to preserve an open border on the island of Ireland. Hard Brexiters insisted on leaving the single market and customs union while rejecting new barriers in the Irish Sea. Those demands were difficult to reconcile.
“ Brexit has produced a paradox. It made the union more politically fragile, but separation more complicated.”
The Irish border conundrum was used to defeat Theresa May’s deal and ultimately bring down her government. Boris Johnson broke the impasse by casually accepting a border down the Irish Sea as the price of a negotiated exit. The Windsor Framework, later agreed by Rishi Sunak’s government, eased some of the practical consequences but did not alter the underlying reality: Northern Ireland now has a different trade relationship with the EU than the rest of the UK, adding to the grievances of the unionist community.
Brexit has therefore produced a paradox. It has made the union more politically fragile, but separation more complicated. An independent
Scotland or Wales would face a stark choice: rejoin the EU and its single market, or negotiate continued participation within the UK internal market. Unless the rest of the UK was itself seeking to re-enter the single market, it would be difficult to do both. For Northern Ireland, reunification would make the Irish Sea barriers more consequential, potentially undoing the benefits that have allowed claims that businesses there have the “best of both worlds”.
The union has survived the Brexit storm, and leaving the UK is now more complicated than it once was. Brexit may have been imposed on an unwilling Scotland and Northern Ireland. But was that a risk worth taking? For some, perhaps it was. Yet something has been broken in the process. For much of the period since the Union of 1707, an unspoken tenet of the British polity was that the centre did not impose its will on a reluctant Scotland. The ambiguity that underscored that reticence – over whether sovereignty rested with the Scottish people or the UK Parliament – has been swept aside.
Brexit also revealed an ignorance at the metropolitan centre of the fragile and complex conditions of Northern Irish politics and, at times, a cynical willingness to exploit the border question for ends other than the well-being of the people of Northern Ireland. While the
immediate crisis has been resolved, the damage to trust will be harder to repair.
For the first time, nationalist parties now lead the governments of all three devolved parts of the UK. Close to half of Scots still support independence, while the Welsh nationalist party Plaid Cymru won the most seats in the May 2026 Senedd elections.
A decade after the Brexit referendum, the stability of the UK is more contingent than ever on circumstance. And circumstance may yet bring another turn of the wheel. A future UK government committed to leaving the European Court of Human Rights could place further strain on the Brexit settlement, including the Trade and Co-operation Agreement, which governs nearly half of the country’s trade. It could also unsettle the Good Friday/Belfast Agreement, which underpins peace and governance in Northern Ireland. How might voters in the devolved nations respond? Brexit has not undone the union. But the strain it placed on the ties that hold it together has not yet run its course.
Philip Rycroft was permanent secretary at the Department for Exiting the EU (2017-19) and second permanent secretary at the Cabinet Office (2015-17).
Catherine Barnard on why leaving the EU has not freed Britain from the gravitational pull of EU law.
The EU is a creature of the law. It is built through treaties, governed by rules interpreted through sometimes expansive decisions of the Court of Justice. Although the British people made their decision in what David Cameron called a “simple yes/no referendum”, translating their decision into international agreements, and then into domestic law, has proved anything but simple.
Britain joined the EU by treaty and left by treaty. When it joined the European Economic Community, the UK did so through the 1972 Accession Treaty. The European Communities Act of the same year gave effect to what became European Union law at home, including two of its defining principles: supremacy, under which EU law takes precedence over conflicting domestic legislation, and direct effect, which allowed individuals to enforce certain European rights in British courts.
Leaving the EU required another dense body of law. The Withdrawal Agreement, negotiated over three years by two British prime ministers, set the terms of departure and made special provision for Northern Ireland, which would stay in the EU customs union. The Trade and Co-operation Agreement, negotiated over nine months during the Covid pandemic, established the basis for the UK’s post-Brexit relationship with the EU. Because the UK treats international and domestic law as separate legal systems, both agreements had to be given effect in domestic law (via an Act of Parliament) before they could operate at home. Both agreements are also premised on UK membership of the European Convention on Human Rights, itself now under threat by commitments from the Conservatives and Reform to withdraw should they win the next general election.
Brexit generated some of the most important constitutional litigation in recent British
history. This began when campaigner Gina Miller challenged the government’s attempt to exercise its prerogative powers to trigger ‘Article 50’, the EU treaty provision governing withdrawal from the union. The Supreme Court ruled that ministers could not act alone and that Parliament had to legislate first. The result was a short act authorising the government of Theresa May to notify the EU of Britain’s intention to leave.
“ More than half a century later, Parliament is again being asked to consider how EU rules should enter the British statute book.”
In the second Miller case, the court ruled that Boris Johnson’s advice to the Queen to suspend Parliament in the autumn of 2019 was unlawful because it frustrated parliament’s ability to perform its constitutional duties without reasonable justification. Together, the two cases exposed the strain that Brexit placed on the UK’s uncodified constitution – a system built as much on convention and restraint as on formal rules.
For the day-to-day operation of the law, however, the most important piece of Brexit legislation was the European Union (Withdrawal Act) 2018. Its aim was continuity. Rather than allow large parts of the statute book to fall away overnight, it took what was, in effect, a screenshot of all EU-derived law and kept it
functioning so that airline safety, food safety, and workers’ rights would be protected after Brexit. Some EU rules were turned off, most notably those governing the free movement of persons. But a large body of EU-derived law remained and continues to this day, with the courts in the UK applying it very much as they did when Britain was a member-state.
That continuity caused significant chagrin to supporters of Brexit. Championed by the Johnson government, the Retained EU Law (Revocation and Reform) Bill sought to turn off all remaining EU law on the statute book unless ministers expressly decided to preserve it. But the more officials looked, the more rules they found, with numbers going up from 2,417 items to nearly 7,000 by January 2026.
The practical risks became clear. Sweeping away thousands of rules in one stroke would have created serious uncertainty and potentially opened a huge chasm in the statute book. As British prime ministers changed and the bill finally became law under Rishi Sunak, the approach had changed. All ‘retained’ EU law would stay, except a few hundred statutory instruments, and the surviving body of rules was renamed ‘assimilated law’.
The political mood has shifted since then. Since Sunak’s premiership, the desire for legislative pull away from the EU has waned, and the argument today is no longer principally about how quickly Britain can diverge from EU law. It is increasingly about when continued ‘alignment’ with EU rules makes economic sense. Things came almost full circle when the Labour chancellor Rachel Reeves announced in March that, where alignment with EU rules served the national interest, Britain should be prepared to accept it. Regulatory autonomy might still be necessary in some sectors, she said, but it should be “the exception, not the norm”.
That shift is already visible in the ‘reset’ pursued by the Labour government, which is now negotiating new agreements with Brussels on agrifood trade, the linking of emissions-trading systems and UK participation in the EU’s internal electricity market. These arrangements will require the UK to engage in ‘dynamic alignment’, meaning that Britain will need to keep its rules up to date with relevant EU legislation, but it will have a limited role in shaping EU decisions. Unlike member-states, it will not have a vote.
Dynamic alignment will need new legislation, the European Partnership Bill, announced in the 2026 King’s Speech. It will provide the powers needed to implement this EU legislation via ‘statutory instrument’. This will take us back to the situation in 1972 when the legislation that brought the UK into the EU gave wide socalled Henry VIII powers to the government to implement EU law.
More than half a century later, Parliament is again being asked to consider how EU rules should enter the British statute book. The difference this time is that the UK is no longer a member-state. It may have a role in ‘shaping’ new EU rules, but it will have no say in making them. Apart from refuelling old political divisions, it raises difficult questions over how to consult and involve the devolved administrations, and how MPs can scrutinise EU rules once they apply in the UK again. Brexit was supposed to settle the question of legal sovereignty. A decade on, the argument has changed rather than disappeared.
Catherine Barnard is a professor of European Union law and employment law at the University of Cambridge and a member of the CER advisory board.
David Miliband on why Britain and the EU need a stronger partnership in a more dangerous world.
Six weeks before the Brexit referendum, I shared a platform with David Cameron, the then prime minister, and I argued that Brexit was a massive geopolitical mistake. The case for Britain to remain in the EU was “about power and influence, and the interests and values they project, in a world that is changing fast”. The speeches were overshadowed, to put it mildly, by an overnight briefing from Downing Street that a vote to leave was a “vote for World War 3”. That claim was counter-productive because it was absurd – but the core argument about the consequences of separating Britain from continental politics is even more true today than it was ten years ago.
At just the wrong time, Brexit weakened Britain, weakened Europe and weakened the West. It weakened Britain because we lost an economic and political force multiplier. It weakened Europe because the UK had been a positive economic and political presence in the EU. And it weakened the West because it created division within Europe just as President Trump was about to introduce division across the Atlantic.
It would be wrong to trace a direct line from the Brexit vote to Russia’s invasion of Ukraine. But it would be right to say that the invasion of Ukraine has exposed the central folly of Brexit’s logic – above all, the assumption that it was possible, even necessary, for Britain to be national or global in its outlook, but not regional. Today, EU unity, strength and finance in support of Ukraine are central to Britain’s number-one foreign policy priority – yet our contribution to, and influence over, a shared European effort must come from outside the room where the decisions are made.
This matters because we face a geopolitical scene marked by a modern version of the ‘Kindleberger Trap’: the fading of a oncedominant global superpower’s influence, creating a power vacuum and stoking instability. In such a world, global public goods – open markets, territorial integrity and climate security – are up for grabs. From the invasion
of Ukraine to the US war in Iran, from China’s assault on the international trading system to the neglect of the global commons such as pandemic preparedness, the scramble for insulation from disorder is accelerating.
“ The question is not whether to turn the clock back, but what future relationship to build instead.”
Mark Carney, speaking in Davos in January 2026, called this a moment of “rupture” – and he was right. But we should also follow his maxim of waking up every morning and thinking “what can I do?” rather than “what has President Trump tweeted?”. For Britain, outside the EU but indispensable to European security, the answer has to begin by acknowledging how the world has changed in the last decade.
The right lens to see today’s world is as ‘multialigned’, with fluid and transactional coalitions working together on different issues. This is, I think, a better description than the idea of ‘multipolarity’, which implies too great a degree of stability. There are many players in this new global situation, often with asymmetric power, as Iran has demonstrated at the Strait of Hormuz. The idea of a balanced, ‘multipolar’ order seems to me to be fanciful. In today’s world we do not have a multipolar equilibrium;
what we have instead is a multi-aligned search for buoys in a choppy sea.
Global hyper-connectedness means that new cross-border risks have emerged, so the need for co-operation between countries is greater than ever. Such co-operative efforts represent countervailing power against the marauding forces of disorder – not just against the 60 or so wars going on at the moment, but also against power plays on every continent.
In facing the new global context, Europe faces internal as well as external demons. The defeat of prime minister Viktor Orbán by the Hungarian people removes one obstacle to EU decision-making in the short term, but the appeal of nationalism and resentment over internationalism and co-operation remains potent. French voters, heading into the presidential election of 2027, hold more than their own country’s fate in their hands. But Britain cannot afford to wait for the French results before acting.
Europe’s biggest security priority today is containing Russia at a time when Washington, in effect, gives it a free pass. The US National Security Strategy under President Trump makes that clear. A central question, therefore, is how to accommodate Ukraine within EU institutional structures – which British governments of both parties have, ironically, supported. That requires
institutional flexibility of a kind the EU has rarely shown: it might mean tiers of membership, or ‘associate membership’. We, in the UK, need to take off our blinkers, clarify our own interests, and engage urgently with these live debates taking place in European capitals.
I have no doubt that Britain’s security and prosperity depend on a much stronger, institutional relationship with the EU. But a ‘reversal’ of Brexit is literally impossible – not just because the deal that we had before 2016 is not on the table now, but also because the EU itself is changing. The question is not whether to turn the clock back, but what future relationship to build instead.
It is vital to combine the strengths of the EU and its member-states, the UK and other European countries outside it, such as Norway. We cannot contain Russia without the EU. We cannot renew our economy by pretending the EU does not exist. We cannot secure our energy future without EU engagement. But all of this requires imagination about a structured institutional relationship that goes well beyond anything currently on offer. We need to recognise that this is a new debate – not a replay of an old one.
David Miliband is president and CEO of the International Rescue Committee, former UK foreign secretary (2007-10) and a member of the CER’s advisory board.
Nicolai von Ondarza on how the EU has adapted to a decade of crises – and how Brexit has left its mark on European politics.
European politics in 2026 look very different from those of 2016. Brexit is part of the story, but not the most important part. The deeper changes came from crises that had little direct connection to the UK’s departure. Covid prompted the EU to pursue common borrowing on an unprecedented scale. Russia’s full-scale invasion of Ukraine turned security, defence and support for Kyiv into central political priorities. Far-right parties have gained influence across the continent, while relations with the US have deteriorated under Donald Trump’s second presidency. For the EU today, Brexit looks less like the defining event of the past decade than one crisis among many that have reshaped how the EU sees itself.
The most important direct consequence of Brexit may be the disintegration that did not happen. When British voters chose to leave the EU in the 2016 referendum, there were fears of a domino effect – that one exit might lead to the unravelling of the whole union. Yet the opposite happened during the withdrawal negotiations. A shared interest in safeguarding the single market and the EU’s other achievements held the remaining 27 member-states together. Rarely, if ever, had they been so united
Brexit also reminded many Europeans of the value of membership. Public support for EU membership – though not necessarily deeper integration – has risen in most member-states. The political chaos in Britain and the economic costs of Brexit have also changed the views of most of Europe’s far-right parties about the merits of leaving the union. Many parties that once entertained the prospect of following Britain out of the EU no longer advocate exit. With notable exceptions, including Germany’s Alternative für Deutschland, the far-right increasingly seeks not to dismantle the EU but to govern and reshape it along more illiberal lines.
Brexit has, however, altered the balance of power within the union. Britain was one of the ‘big three’ member-states and often the partner of choice for economically liberal
and/or Atlanticist governments. Its departure increased the relative influence of France and Germany, with many of Britain’s former allies turning increasingly to Berlin. It also gave rise to smaller coalitions – ‘minilateral’ groups – within EU politics. Some of these groupings predate Brexit, but they acquired greater influence after the UK’s departure. The Visegrád Four, the fiscally conservative ‘Frugal Five’ and the NordicBaltic Eight have each sought, in different ways, to amplify their collective interests. In the past, many of their members might have worked with – or even through – London, not least during negotiations over the EU budget.
“ Brexit, in the end, did not reconfigure the EU so much as reveal its resilience.”
More recently, Russia’s war against Ukraine and growing tensions with the US have encouraged the use of flexible formats, only partly tied to EU institutions. One reason is the will to involve the UK, which can no longer participate in EU decision-making as it once did. In foreign, security and defence policy, the traditional ‘E3’ – France, Germany and the UK – has seen a resurgence as an important channel. Wider configurations, such as the ‘E5’ or Weimar Plus, have brought together France, Germany, Poland, and the UK,
sometimes joined by Italy or Spain, alongside representatives of the EU and/or NATO. These groups have become important conduits for co-ordinating common European positions on major foreign-policy issues.
The partial replacement of UK positions by groups of smaller member-states also meant that Brexit did not lead to a fundamental unblocking of European integration. The UK was often the most visible opponent of closer integration, even if at times it wielded only a symbolic veto. But on many issues, other European governments were content to hide behind British objections. After Brexit, some member-states such as the Netherlands have taken a more prominent role themselves.
There are two notable initiatives that the British government would probably have blocked or significantly altered had the UK remained a member. The first is the Covid-era Recovery and Resilience Fund, financed through large-scale common borrowing that provided grants and loans to member-states, enabled by a FrancoGerman political compromise. The second is the expansion of the EU’s role in defence. This includes joint ammunition initiatives and the SAFE initiative, the €150 billion loan programme to support national defence spending and common procurement. The UK might have supported the broad objective of strengthening European defence, but it would probably have resisted giving the European Commission a large role in doing so.
In other respects, the irony is that the EU has become more like Britain – and Britain more
like the EU. The rightward shift in European politics has led the union to harden its approach on asylum and migration policy, including agreement to establish ‘return hubs’ in third countries for people with no right to remain on the EU’s territory.
On economic policy, the EU has been busy negotiating new free-trade agreements as it seeks to diversify its relationship in response to Trump’s tariffs. The EU-Mercosur trade agreement has been provisionally applied, while negotiations with India and Australia have concluded early this year. The EU’s competitiveness agenda also increasingly focuses on simplifying regulation, reducing business red tape and deepening the single market – priorities championed by successive British governments pre-2016.
Brexit, in the end, did not reconfigure the EU so much as reveal its resilience. The union remains prone to disagreement and frequently slow to act. But it has also become more adaptable and flexible in confronting many of the crises on its doorstep. In an age of renewed great-power competition, the EU remains the preferred vehicle for Europe’s mostly small countries seeking to defend their interests by working together.
Nicolai von Ondarza is a political scientist and head of the EU/Europe research division at the German Institute for International and Security Affairs (SWP).
Julian King on why closing gaps in UK-EU security co-operation is a strategic necessity.
The world has changed dramatically since 2016, particularly when it comes to defence. But many of the security challenges that confronted Europe a decade ago remain very much live. At the time of the Brexit referendum, Europe was in the middle of a wave of lethal terrorist attacks. Governments were grappling with radicalisation and the spread of political disinformation online. Major cyberattacks were spilling over into the wider economy. And Europe’s leaders were starting to realise how important it was to protect critical infrastructure and build resilience across our economies and, indeed, societies. We learned, sometimes the hard way, that such threats were most effectively tackled working together, especially with like-minded partners.
Ten years later, the threat from terrorism and serious organised crime has not gone away across Europe. Events in the Middle East continue to fuel radicalisation. Attacks on Jewish communities have become more frequent. Beyond Ukraine’s borders, Russia is locked in a grey-zone struggle with the West, increasingly taking the form of direct action against European countries. Cyber risks are accelerating, not least thanks to artificial intelligence. And economic security – reducing dependencies and strengthening resilience –has moved from being a peripheral concern to the centre of the European political debate.
These challenges are still best tackled together. Law enforcement and security agencies across Europe continue to work closely. But one factor has changed. Brexit has placed the UK outside the dense network of co-operation on security issues – and critical information-sharing arrangements – that EU member-states had built over many years and that underpin collective European security.
The Trade and Co-operation Agreement, which governs the UK’s post-Brexit relationship with the EU, preserved some of those links, but with limits. The EU-UK summit in May 2025 reaffirmed the importance of co-operation in this area. It promised renewed efforts to
accelerate exchanges of criminal-records data and information relating to terrorism, including through enhanced links with Europol, the EU’s police agency.
“ The UK and the EU face shared threats to our shared values.”
Important gaps nonetheless remain. One that merits more political attention is the absence of a real-time alert system between British law-enforcement services and those of other European countries about persons of interest. This may sound technical, but it is a real security gap. It affects the ability of authorities to identify and stop serious criminals and pursue counter-extremism and counterterrorism investigations across the continent.
When it left the EU, the UK lost access to major common databases, including the Schengen Information System (SIS). The database holds tens of millions of active alerts from police, border guards and other security agencies across Europe, including arrest warrants, information on missing persons, stolen identification documents and firearms. It is the backbone of European law-enforcement co-operation, processing literally billions of enquiries each year.
As a country outside the union, the UK cannot simply rejoin SIS. Instead, British authorities currently share alerts with their EU counterparts via the international Interpol system. This is not an adequate substitute. The number of EU alerts on persons of interest received by the UK since Brexit has fallen by 90 per cent compared with the number circulating through SIS. That adds up to around 400,000 missing alerts per year, including discreet checks used in counter-terrorism and counter-radicalisation investigations. Those ‘missing alerts’ are no longer automatically checked when someone is stopped by British police or crosses the UK border. The result is about one billion missed opportunities for checks each year.
This is a significant gap that leaves the European continent less secure. It is serious enough to warrant looking again at the options for a shared real-time alert exchange capability. Rebuilding this capability need not require the UK to rejoin SIS. The EU already allows the security and migration databases to be interoperable on a ‘hit/no hit’ basis, allowing authorities to identify relevant information while preserving the integrity of the underlying systems. There are viable technical ways forward.
What is missing is the political impetus. The past decade has been marked by a failure to distinguish between the legal consequences of Brexit and the wider strategic case for security co-operation. In the immediate aftermath of the referendum, I was involved as the commissioner responsible for the security union – and so must take part of the responsibility – in the European Commission’s proposal to exclude the UK from the Galileo satellite-navigation system. Whatever the legal arguments at the time, the justification that the UK was not a trusted security partner was misguided. Developments since then have only proved this.
The UK and the EU face shared threats to our shared values. As they continue to reset their wider relationship, they should continue to build a more trusted partnership on security. Closing the gap in real-time alerts would be a practical test of whether the reset can deliver on its promise.
Sir Julian King is a specialist partner at Flint Global, a former European commissioner for the security union (2016–19), and a former British ambassador to France (2016). He is also chair of the CER’s advisory board.
Ian Bond on how Britain can defend shared European security interests from outside the EU.
A few days before the Brexit referendum, I wrote about the troubled international environment then facing the UK, from instability in the Middle East to the crisis in Ukraine. “All of these problems are common to the UK and its EU partners,” I argued. “Not one of them would be solved, or have less impact on the UK, if Britain were to leave the EU.”
Ten years on, that remains true. So Britain and its European partners have ended up working together more often than not – in response to Russia’s full-scale invasion of Ukraine, through successive crises in the Middle East, and as the United States reduces its contribution to Europe’s security.
Nonetheless, Brexit has cost the UK some influence. Britain has not been able to retain the seat close to the table that then prime minister Theresa May proposed in September 2017. She wanted the option of agreeing joint positions on foreign policy issues, and the ability to work with the EU on mandate development and detailed operational planning for civilian missions and military operations under the EU’s Common Security and Defence Policy (CSDP). At the time, that was too much for the EU to swallow in the context of the mistrust and anger caused by the Brexit vote. Britain’s impending withdrawal enabled the EU to move ahead with some forms of defence co-operation that London had previously blocked, including Permanent Structured Co-operation (PESCO), which was launched in 2017 and allowed a vanguard group to move ahead with defence projects.
Boris Johnson then decided to exclude foreign and defence policy co-operation from the Trade and Co-operation Agreement, the treaty that governs the UK’s post-Brexit relationship with the EU. The reasons were partly tactical: his team did not want to appear demandeurs for a relationship in those areas, for fear that the EU
side would then demand concessions elsewhere in return. But they were also ideological – some in Johnson’s circle believed that the UK’s foreign policy relationships should be conducted with individual member-states, not EU institutions.
“ Even where strategic interests align, the mistrust of the Brexit years has not disappeared.”
Since Brexit, and particularly since Labour took office in the UK in 2024, formal and informal contacts between the EU and the UK on foreign policy issues have increased. After Russia’s February 2022 invasion of Ukraine, Liz Truss became the first UK foreign secretary to attend an EU Foreign Affairs Council since the UK’s departure, and the two sides began working more closely to co-ordinate the now-separate sanctions regimes. David Lammy, when he became foreign secretary, agreed with Josep Borrell, then the EU’s High Representative for Foreign Affairs and Security Policy, to hold sixmonthly ministerial meetings, alongside regular official-level dialogues on issues including Russia/Ukraine, the Indo-Pacific region and hybrid threats.
The Security and Defence Partnership (SDP) agreed at the EU-UK summit in May 2025 seemed to mark a step change. Among other things, it promised further dialogues from ministerial level downwards, opened the possibility of UK participation in EU civilian and
military CSDP operations, and committed both sides to explore closer links between the UK and the European Defence Agency, which could give the UK access to some EU defence capability development programmes.
More than a year after the SDP was agreed, however, much of its potential remains unfulfilled. The foreign secretary has not become a regular attendee at EU Foreign Affairs Council meetings. Nor has the UK moved quickly to negotiate a Framework Participation Agreement to take part in EU crisis management operations.
Most importantly, talks on British participation in SAFE, the EU’s programme for joint procurement of military systems and munitions, broke down after the Commission sought a large up-front financial contribution from Britain, and London concluded that the price was too high. The result is that one of Europe’s largest defence industrial bases remains outside an important programme designed to enhance European defence capabilities. It is a missed opportunity – and a reminder that, even where strategic interests align, the mistrust of the Brexit years has not disappeared.
In the absence of comprehensive co-ordination through an EU framework, various bilateral
and minilateral relationships have appeared or evolved, designed to enable the UK to work with its partners. These formats are a pragmatic response to the desire of many European countries to keep the UK involved in European security issues, at a time of crisis. But they can create their own problems. Some countries resent being excluded from groupings such as the E3 – France, Germany and the UK – and worry about the evolution of a directoire that shapes European foreign policy without giving the EU institutions or all member-states a voice.
Brexit has done less damage to UK-EU cooperation on foreign and defence policy than in many other areas, partly because the EU’s Common Foreign and Security Policy remains largely inter-governmental. But that is not a reason for complacency. The UK and the EU could do more to align their responses to shared threats and to increase their co-ordination in mitigating the risks to Europe’s security.
Brexit changed Britain’s institutional position in Europe, but it did not change Europe’s geography. What threatens the EU still threatens the UK, and vice versa.
Ian Bond is deputy director of the Centre for European Reform.
Nick Butler on why the UK and the EU need a more resilient energy and climate partnership.
Despite Brexit, the UK and the EU remain close partners on energy and climate policy. They share the same broad objectives – decarbonisation and net-zero emissions of greenhouse gases by 2050 – and rely on many of the same tools. Both operate carbon-pricing systems. The EU has introduced a carbon border adjustment mechanism, while the UK is due to launch its own version in 2027. There are some differences in the detailed application of these tools, but none should hamper closer alignment as part of a wider reset of their post-Brexit relationship.
The physical links are already substantial. Britain has ten electricity interconnectors linking it to seven neighbouring markets, including France, Norway and Denmark. In the year to September 2025, they supplied around 43 terawatt-hours of electricity to Britain – about 13 per cent of its total power consumption.
A single European energy policy – as distinct from climate policy – remains out of reach. The energy mix in each country varies widely according to natural resource bases, political choices and local preferences. Germany, Italy and Austria have turned away from nuclear power, while France relies on an extensive fleet of nuclear plants for much of its electricity. Coal retains a role in parts of central and eastern Europe and continues to provide over 20 per cent of electricity supply in Germany. Spain is ahead of the rest of the continent in developing low-carbon supplies of solar and wind power, while Germany has promoted green hydrogen as a key component of a decarbonised economy.
Entrenched national interests also remain powerful. Across the continent, the power of legacy energy providers – national champions and state-owned companies such as EDF in France – limits open trade, especially in the supply of electricity. Although crossborder electricity trading has grown between
member-states, the EU remains some distance from a truly integrated energy market. The long-standing ambition of building a common connected European power grid –first floated by Angela Merkel in 2009 – is still only partly realised.
“ The case for closer co-operation has become more urgent as Europe’s energy vulnerabilities have been exposed.”
The UK has its own distinctive energy mix, with fossil fuels still accounting for just over 75 per cent of its energy needs, while offshore wind power has expanded rapidly, and successive governments have sought to revive the oncesuccessful nuclear industry. The result is not out of line with the variety seen in the rest of Europe.
The case for closer co-operation has become more urgent as Europe’s energy vulnerabilities have been exposed. Russia’s full-scale invasion of Ukraine forced Europe to reduce its reliance on Russian supplies and turn increasingly to Norway and the US. Between 90 and 95 per cent of the EU’s daily oil and gas consumption relies on trade flows – a strategic vulnerability in times of instability. In 2024, net imports met 57 per cent of the EU’s energy needs. Its dependence
on imported natural gas was higher still, at almost 86 per cent.
Britain is less exposed than the EU as a whole – with net import dependency at 43 per cent in 2025 – but the gap is narrowing as North Sea production declines. Trade with Russia is much diminished since the invasion of Ukraine, leaving Norway and the US as the main suppliers of natural gas, for the moment, to both the UK and most EU countries. The war in Iran and the disruption in the Strait of Hormuz have exposed the risks of reliance on imported products such as diesel oil and jet fuel. Both the UK and the EU have come to rely on the refineries built over the last 20 years in the Persian Gulf for supplies of both products. Renewal and upgrading of the refinery sector across Europe are likely to be one consequence of the conflict.
None of this means that the UK and the EU should pursue a single energy policy. This is unattainable given the strength of entrenched national interests and preferences. Climate policy could, however, be usefully ‘reset’ on a pan-European basis. While Europe must reduce emissions, policies that inflict unnecessarily
high upfront capital costs on industries already under pressure from high energy prices are damaging competitiveness, while doing little to reduce the risks of climate change on a global level. The EU accounted for close to a fifth of the global economy and only around 6 per cent of emissions in 2024. The UK contributes around 3.3 per cent of global GDP and produces less than 1 per cent of emissions.
The climate does not recognise national or regional boundaries. A cleaner Europe matters, but it will not be enough on its own. A UK-EU reset focused on policies that would change the global situation through research and deployment of technologies capable of bringing down the costs of the energy transition would be a major achievement. It would require a clearer recognition that the EU and Britain –whether a formal member of the union or not –have a deep common interest in strengthening their energy partnership.
Nick Butler is an energy economist, a visiting professor at the Policy Institute at King’s College London, and the co-founder and former chair of the CER.
Peter Kellner on how British voters now see Brexit differently – and why regret is not the same as reversal.
The British public’s verdict is increasingly clear. Brexit was a mistake. Ten years after the referendum, voters now say by two to one that the country was wrong to leave the European Union.
YouGov has tracked the question since 2016. Its latest survey, a decade later, records the lowest level of support for Brexit so far. Just 29 per cent of Britain’s electors say that Britain was right to vote to leave the EU – the first time the figure has dipped below 30 per cent. Fifty-eight per cent say it was wrong to do so – the joint highest figure so far.
But the headline figures conceal important differences by age, social class and political allegiance, as YouGov research shows. Almost one in three Leave voters have either changed their mind or now harbour doubts about the wisdom of Brexit. The generational gap is stark: voters under 25, who had no say in the 2016 referendum, oppose Brexit by ten to one, while those aged 65 and older are narrowly in favour.
The shift is not confined to younger or more affluent voters. Manual workers in England’s former industrial heartlands voted heavily for Leave a decade ago. Today, those classified as having ‘routine’ occupations divide by 46 to 36 per cent against Brexit, even though they remain less hostile than voters in ‘higher’ or ‘intermediate’ occupations. Nor have proEuropean Conservative voters disappeared. More than one in three voters who voted Conservative in 2024 say Britain was wrong to leave the EU, even if their voices are seldom heard on the opposition benches in the House of Commons.
The reasons for the change of heart are not difficult to find. A tracking study by NatCen
shows how disillusionment set in among many Leave voters. In 2017, while the UK’s post-Brexit relationship was still being worked out, 57 per cent of Leave voters expected the economy to improve and immigration to fall. By 2024, four years after the UK left the EU and the subsequent transition period had ended, most Leave voters felt that those hopes had been dashed.
“ Disillusionment does not necessarily mean that voters want Brexit reversed.”
Disillusionment does not, however, necessarily mean that voters want Brexit reversed. At first sight, that appears precisely what most voters do want. When YouGov asked in April whether people would “support or oppose Britain rejoining the European Union”, 55 per cent supported the idea and 33 per cent opposed it. The figures for Leave voters were almost identical to those on whether Brexit had been right or wrong: support 22 per cent, oppose 67 per cent.
Yet for many voters, support for rejoining may really mean a desire to turn the clock back to the position that Britain occupied before 2016: inside the EU, but outside the euro and the Schengen passport-free area.
YouGov tested this directly in July 2025. When voters were asked simply whether Britain should rejoin, 54 per cent supported the idea and 32 per cent opposed it. But when they were
told that re-entry could require the UK to join major policy areas from which it had previously secured opt-outs, support fell to 36 per cent and opposition rose to 45 per cent. Among Leave voters, only 10 per cent supported rejoining on those terms, while 76 per cent opposed it. Even among Remain voters, support was no longer overwhelming: 59 per cent backed re-entry and 29 per cent opposed it.
The precise terms of any future accession negotiation cannot be known in advance. In theory, Britain might be expected to join both the eurozone and the Schengen area. In practice, eight of the current 27 memberstates are outside the eurozone and two remain outside Schengen. It is possible, if not likely, that Britain could negotiate arrangements allowing
it to keep the pound and remain outside Schengen. But it could not assume that its previous opt-out would simply be restored.
The larger point is political. Rejoining the EU would not be a single decision. It would be a lengthy, complex and at times difficult process. Polling figures suggest that sustaining public support for the process cannot be guaranteed. It would need determined and effective political leadership to have any chance of success. A decade after the referendum, the British public increasingly appears to regard Brexit as a mistake. But recognising a mistake is easier than agreeing how to correct it.
Peter Kellner is a political analyst and a former president of the polling company YouGov.
Nathalie Tocci on why the next phase of UK-EU relations needs a clearer political endpoint.
A decade has passed since British citizens voted to leave the EU – a decade in which Europe’s world has been turned upside down. Leaders across European capitals, including London and Brussels, openly acknowledge the strategic case for closer ties. Yet remarkably little has changed in the relationship between the EU and the UK. Europe’s leaders and institutions understand the need to work together with the UK. But the lack of meaningful action suggests that the current approach may be a dead end.
In the months after the 2016 referendum, many scholars, commentators and practitioners – myself included – believed that a new EUUK relationship should start with security and defence. Economic and trade talks were always likely to make for a difficult, lopsided negotiation. After all, European integration has gone furthest in the economic sphere, through the single market, and any negotiation between a 27-member union and a single European country, however large, was bound to be asymmetrical.
Security and defence appeared to offer a more fertile ground. The UK remained one of Europe’s leading military powers, with a nuclear deterrent, significant armed forces and a developed strategic culture. By contrast, EU countries had collectively long struggled to turn their military ambitions into concrete actions. There was an obvious case for a mutually beneficial partnership. But this never materialised, not least because the Conservative governments of those years ruled out any structured engagement with the EU in this area.
Since then, Europe has lurched from crisis to crisis. It faces Russia’s war in Ukraine and its wider imperial ambitions in eastern Europe. It faces a United States that, under the second Trump administration, has not merely disengaged from European security but actively betrayed European trust in the
transatlantic alliance – most egregiously over Ukraine and through its threats to use force to take Greenland. Across Europe, far-right forces have received support from both Russia and the MAGA movement. European leaders have long acknowledged that these interlinked threats can only be overcome if the EU and the UK act together.
“ The time has come to admit that the current approach has reached its limits.”
The change of government in London in July 2024 created an opportunity to reset the relationship. Many hoped that both sides were finally willing to turn the page. After all, the EU and the UK share the same strategic outlook and support for Ukraine after Russia’s full-scale invasion. When British and EU leaders met at Lancaster House in May 2025, at the first such summit since Brexit, they agreed an EU-UK security and defence partnership, which was modelled on the EU’s agreements with other ‘like-minded partners’ such as Norway. The partnership, in principle, opened the door to British participation in Security Action for Europe (SAFE) – a €150 billion loan fund supporting defence projects involving several EU member-states or third countries with a partnership agreement. And while the ‘reset’ promised future deals on agrifood trade, carbon pricing and youth mobility, it was
the need for closer co-operation on security and defence that gave the effort its strategic purpose.
A year later, the record is mixed. The UK and the EU remain practically aligned on most major foreign and security policy issues. The security situation has not improved: hopes for a ceasefire in Ukraine are fading; the transatlantic rupture is deepening, particularly since the Greenland crisis; and despite a fragile ceasefire, the USIsraeli attack on Iran has created bloody chaos in the Middle East and closed the economically vital Strait of Hormuz. Collective European action, often with the UK co-leading alongside France, has emerged through coalitions of the willing operating outside existing EU and NATO frameworks. Yet there is still little to report on EU-UK co-operation. Negotiations over the UK’s participation in SAFE first failed at the end of last year. They were restarted this year, but have not yet delivered an agreement.
Where proposals have emerged, such as the UK’s recent suggestion to re-enter parts of the single market for goods, they have been underwhelming, because the free movement of goods is only one of the four freedoms in the single market. The UK has attempted to cherrypick from the EU since Brexit. One wonders what makes London believe that doing the same thing over and over again will lead to a different response from Brussels.
This raises a difficult question: is it time to acknowledge that there are critical, perhaps insurmountable, limits to the depth and breadth of the EU-UK relationship so long as membership remains expressly excluded?
In Britain, ruling out membership emboldens committed Brexiteers to obstruct closer cross-Channel ties, while placing supporters
of deeper integration on the defensive. ProEuropeans are left advocating incremental improvements while avoiding a larger argument about the country’s future, for fear of being misunderstood. In Brussels, meanwhile, Britain’s rejection of membership consigns it to the category of a third country: an important partner but never a genuine priority. This is not out of spite towards the UK. More crudely, it is because relations with the UK are not perceived as being as important as those with the US, China or other major powers, whose economic and political leverage over the EU is far greater than that of the UK.
Nor are relations considered fraught enough to compel Brussels to go the extra mile. European leaders remain wary of offering the UK a privileged arrangement that could set an unwelcome precedent for memberstates tempted by opt-outs of their own. Even a decade after the Brexit referendum, those instincts are deeply embedded in the EU’s institutional thinking. There is simply no incentive for the EU to offer meaningful concessions – and little, if any, leverage through which the UK can cajole the EU to do so.
Two years after the Labour government announced the reset, the time has come to admit that the current approach has reached its limits. Unless the UK embarks on a path that treats membership as a genuine possibility, the structural limits of the relationship will continue to outweigh the political case for any strategic convergence across the Channel. In today’s world, neither side can afford that.
Nathalie Tocci is professor of practice at the Johns Hopkins University SAIS, a former special adviser to EU High Representatives for Foreign Affairs, and a member of the CER’s advisory board.
Catherine Day on what Britain must be prepared to accept if it wants a closer relationship with the EU.
Although the warning signs were there, the Brexit vote came as a shock to the EU. After more than four decades of working together, the UK’s decision to leave felt like a death in the family – and a rejection of the union’s basic principles of pooling sovereignty to deliver peace and well-being as well as benefits such as economic and social cohesion. Yet Brussels did not spend long crying over spilt milk. It quickly concluded that the UK could not choose an à la carte menu of options in the exit negotiations and set out its terms accordingly. The EU was open to different forms of postBrexit relationship. In the end, the British government chose a relatively distant one.
Views will always differ across European countries about what the EU is and what it should be. But Brexit has clarified the benefits of membership and exposed the enduring costs of leaving. No other member-state is today seriously considering exit. The EU, meanwhile, has moved on quickly with its own agenda. In some respects, collective decision-making has become easier without the UK, particularly on initiatives with major budgetary implications: the common purchase of vaccines during Covid, the post-pandemic economic support for member-states funded through common borrowing, and more recent steps on security and defence. Some of these are measures that British governments would probably have found hard to support and might well have resisted.
This is not to say that the EU has not suffered from Britain’s departure. The UK’s political worldview, and the technical expertise of its officials, are genuinely missed in Brussels. London’s constant challenge to each and every Commission proposal – forensic, sometimes infuriating – more often than not improved the quality of the final outcome. It forced other member-states to be very precise about what they actually wanted.
Ten years on from the referendum, the world looks very different from how it looked in 2016.
Russia’s invasion of Ukraine has highlighted Europe’s inability to defend itself, while America’s assault on the global trading order has pushed both the EU and the UK to diversify relations with countries around the world. The challenge to democratic values from autocratic powers, and the growing assertion of might over right, has also reminded the EU of the importance of its rules-based system, grounded in rights and equality principles. Against that backdrop, the UK’s history, geography and shared values make it a natural partner for the EU. Both sides know that they need closer co-operation to be able to secure the future for their citizens. It is not surprising, then, that there is growing talk about closer ties – and even calls in the UK to rejoin.
“ Brexit has clarified the benefits of membership and exposed the enduring costs of leaving.”
Is it time for a rethink on both sides? I would leave aside the question of future British membership. The UK has not changed enough to be ready to accept the EU as it is: a system where the member-states work closely together in key areas to deepen solidarity between them while respecting each other’s history and traditions. This integration is likely to continue in certain areas even though the
union is already heavily stretched on a range of priorities, not least future enlargement. But the appetite for a closer relationship is growing in many areas – from trade, energy, AI and technology, to security and defence.
Building new ties will be easier in some areas than in others. In many fields, the UK has retained the common rules under which it operated as a member-state, which should facilitate agreement. But as the larger partner, the EU is unlikely to extend many of the benefits of membership unless the UK accepts the accompanying constraints. The concern about selective participation – or British ‘cherry-picking’ – is real. An à la carte approach could erode the common base built over decades and quickly undermine the single market. The UK will have to accept that the more it wants, the more conditions will be attached.
There is likely to be a degree of flexibility within the range of the various arrangements that the EU has with other countries – such as the
customs union, the European Economic Area and others. But it is hard to see the EU offering full access to the single market without free movement of people. The ability to live freely in another EU country goes hand in hand with the right to do business, trade and invest across EU borders, thus bringing all the aspects of economic life together in one single market.
In 2026, relations between the EU and the UK have calmed and are increasingly shaped by the upheavals elsewhere in the world. The EU is a political as well as an economic project. Brussels will be open to building a new relationship with Britain, but it will not be in a hurry. It will watch the British political debate closely and seek an agreement that offers lasting benefits to both sides. The more Britain wants from that relationship, the more it will have to accept in return.
Catherine Day is a former secretary-general of the European Commission (2005-15) and a member of the CER’s advisory board.
Daniela Schwarzer on the practical agenda that could make the UK and the EU stronger together.
A decade after the Brexit referendum, the central question in EU-UK relations is no longer how to manage separation. It is whether Europe can afford fragmentation in a world of geoeconomic competition, technological rivalry and growing security threats. The UK and the EU are two of Europe’s most important economic and strategic actors. If they remain divided in areas where their interests overlap, Europe will be collectively weaker.
The UK remains one of Europe’s leading diplomatic, military and intelligence powers. The EU, meanwhile, continues to develop its foreign policy tools and economic statecraft. Co-ordination on sanctions, intelligence and diplomatic issues has been effective in recent years, with Russia’s full-scale invasion of Ukraine giving it fresh impetus. Today, member-states and the UK co-operate in bilateral formats, through NATO, and in minilateral groupings, which are becoming more prominent as US support for Ukraine has become less certain under Donald Trump’s second presidency.
Leaders on both sides increasingly recognise that Europe’s challenges – above all the need to rebuild a European security order –cannot be met through fragmented national responses alone. The Security and Defence Partnership, agreed between the two sides in May 2025, created a framework for stepping up co-operation on foreign policy and security issues. But the partnership between the EU and the UK needs to go further. The next phase of the ‘reset’ should focus on the broader agenda of shared resilience, economic security and competitiveness.
Economic security is where today’s pressures come together most clearly. The EU and the UK both depend on China and other external suppliers for critical inputs, from semiconductors and telecoms equipment
to pharmaceuticals and rare-earth minerals. Emerging technologies – such as AI – and access to digital infrastructure are becoming key sources of economic and geopolitical power. And recent crises, from the pandemic to the energy shock, have exposed the fragility of supply chains and underlined why economic resilience is no longer a question of efficiency, but a matter of national security.
“ If the two sides remain divided in areas where their interests overlap, Europe will be collectively weaker.”
How Europe ramps up its defence-industrial capacity is another test. Despite higher defence spending commitments, Europe’s defence landscape remains fragmented, marked by duplication, inefficiency and inadequate scale. Brexit has added another layer of separation, making it harder for the UK to join emerging European defence-industrial initiatives.
Then there is the risk that Europe loses the ability to shape an international economic order, in which economic coercion, export controls, subsidies and strategic competition are becoming all too common. If the EU and the UK remain divided across technology, regulation and supply chains, both will have less bargaining power and Europe will have less say over the rules of the new global economy.
The EU and the UK can – and should – respond to these challenges with concrete steps. A dedicated EU-UK Economic Security and Resilience Dialogue would be the place to start. It could strengthen co-operation on supply chains, industrial policy and economic security, from co-ordination of policies on critical raw materials and export controls, to foreign investment screening and energy security. Managed well, such a forum would provide strategic direction to the EU-UK relationship while complementing engagement through the G7 and bilateral formats.
Technology co-operation should be the second pillar. A comprehensive Technology and Innovation Partnership could co-ordinate technology standards, support joint projects in areas such as AI and advanced computing, and deepen links between innovation ecosystems and venture-capital markets. It should also explore UK participation in European scale-up financing instruments, including the proposed Scaleup Europe Fund.
Both sides should also agree to treat regulatory co-operation as a source of geoeconomic power. One of the less visible consequences of Brexit has been ‘passive divergence’ in regulatory standards, as new EU legislation gradually creates barriers even when the UK has made no deliberate decisions to diverge from EU rules. Early-warning mechanisms, regular exchanges between regulators and more systematic scrutiny of future rules would help preserve compatibility in important areas such as climate policy, digital regulation, financial services and product standards.
Co-operation on energy security and resilience should be another pillar. Both sides have an interest in working together on electricity interconnectors, clean-technology supply chains, strategic infrastructure and coordination with partners such as Norway.
Finally, defence-industrial co-operation needs more flexible arrangements. The UK should be able to participate in selected European defence-financing initiatives, procurement programmes and capability-development projects where shared interests are clear. Closer engagement with the European Defence Agency and greater co-ordination on defence supply chains would reduce duplication, improve interoperability and strengthen Europe’s deterrence capacity.
The lesson of recent years is that the existing machinery in post-Brexit relations is too often ill-suited to issues that are strategically important but politically sensitive. The two sides should prioritise finding practical ways to work together in areas where shared interests are clear, even when the politics are difficult. The next phase of the EU-UK relationship will be judged not by how far it resolves old disputes, but by whether it helps Europe as a whole to become more resilient, more competitive and more capable of acting in a dangerous world.
Daniela Schwarzer is a member of the executive board of the Bertelsmann Stiftung.
Charles Grant on how much closer UK-EU relations can go – and what could make a more ambitious partnership possible.
Ten years after the Brexit referendum, UK-EU relations are cordial. But the reset in the relationship – heralded at the UK-EU summit in May 2025 – has so far been modest. Britain has rejoined the Erasmus exchange programme, and will probably agree deals soon on youth exchange, emissions trading systems and veterinary standards. Keir Starmer’s government has stuck to its red lines –no customs union, single market or freedom of movement – which, as far as the EU is concerned, means there cannot be big changes to Boris Johnson’s Brexit settlement.
Over the past year, Starmer and his ministers have started talking about the EU in more positive terms. Officials have even floated, vaguely, the idea of rejoining the single market for goods (to which the EU says, if you want to be in one bit of the market, you have to be in all of it). But there has been no serious or coherent British plan for getting significantly closer to the EU.
Britain’s political turmoil has not helped. European leaders ask if there is much point in doing deals with a Labour government, when in a few years’ time a future prime minister Nigel Farage could tear them up. The EU has also had its hands full: Russian militarism, America’s disengagement from Europe, China’s assault on European manufacturing, the rise of the far right and economic under-performance are all more important than revising the Trade and Cooperation Agreement that Johnson negotiated. In any case, the EU regards that as a perfectly good deal.
British politicians complain that the EU is an inflexible partner, but the EU has genuine concerns about the integrity of the single market – it worries that if a country is allowed into just parts of it, the whole is weakened. This stems partly from a strong feeling of insecurity caused by surging support for far-right parties across Europe. EU leaders fret that if the British get some of the benefits of membership
without having to swallow free movement, Marine Le Pen and others like her will ask for the same. As one official told me, “given the gravity of the threats we face, we have to focus on protecting the immediate interests of the member-states, rather than those of third countries, or countries that want to join.” Too bad for Britain and Ukraine.
“ There has been no serious or coherent British plan for getting significantly closer to the EU.”
In security and defence policy, however, the ‘reset’ has been quite successful. Thus the UK has worked closely with the EU on sanctions against Russia, signed a Security and Defence Partnership with the EU and will probably participate in the EU’s €90 billion loan for Ukraine, two-thirds of which is for defence –though French opposition kept Britain out of SAFE, an EU scheme designed to encourage common defence procurement. Britain and France have led efforts to put together coalitions of the willing for a reassurance force in Ukraine, and a naval force for the Strait of Hormuz – though neither can start work until there is a peace settlement to police. The E3 –Britain, France and Germany – have played an important role in the diplomacy surrounding Ukraine. The UK has also struck bilateral defence partnerships with several member-states, including France, Germany and Poland. And, of
course, it remains a major player in NATO and the Joint Expeditionary Force, alongside the Nordics, Baltics and Dutch.
Given the UK’s contribution to European security, and how valuable that is in the current geopolitical situation, some British politicians reckon it should buy a certain amount of goodwill from the EU. In particular, they think the EU should be more open to offering the UK a better trade agreement.
But that is not how it looks to the Commission, France, Germany and probably a majority of member-states. Their view is that the UK engages in European security because it is in its own interest to do so – and that there is no particular reason why good co-operation on defence should trigger a different trade deal. They then add that if the UK rethought its red lines, a different sort of economic relationship could be possible. They tend to point to the Norway model, based on participation in the single market for goods and services, or to a customs union. They do not point to ‘the Swiss model’, which the EU has doubts about. The Swiss are essentially in the single market for goods but not that for most services, which breaches the EU dogma of the four freedoms being indivisible.
The Nordic, Baltic, Dutch and Irish governments sometimes say the geopolitical and economic benefits of much closer UK-EU ties are so important that the EU should be willing to compromise its principles. But most memberstates seem to think that the success or otherwise of the British economy is not of great concern to the EU; and that if the current version of the trade agreement gives Britain economic problems, that is simply the consequence of leaving. One also hears the view, especially in France, that voters should see that Brexit hurts, so they are dissuaded from following the same path.
I would argue that this view is short-sighted. The fate of Britain’s economy matters for the 27. It is not in the EU’s interest to have the UK – its
second largest trading partner, with which it enjoys an annual goods surplus of €200 billion – stagnating on the edge of Europe. For all its difficulties, Britain has real economic strengths that can help to boost the wider European economy, like innovative companies in AI, life sciences, fintech and precision engineering. Its venture capital industry, universities and financial services sector are the best in Europe. Both sides would benefit from the increased competition and dynamism that closer economic ties would foster. Economics, after all, is not a zero-sum game.
Evidently, the political shenanigans in the UK do not encourage EU politicians to come up with bold and original ideas for the relationship. European politicians see contradictory signals: roughly two-thirds of British voters regret Brexit, yet the anti-EU Reform UK is leading in opinion polls (though with substantially less than 30 per cent). Europe will be a dividing line at the next general election. It is plausible to imagine that the broadly pro-European camp – Labour, Liberal Democrats, Scottish and Welsh nationalists and Greens – could triumph over the anti-EU bloc. But the divisions in British politics over Europe are likely to persist beyond that election.
In the medium term, the UK will need a bespoke deal, probably closer to Switzerland than to Norway, since Britain is unlikely to accept EU rules wholesale in services sectors where it has a comparative advantage, from the City of London to technology and AI. This will require the EU to be imaginative – perhaps taking inspiration from the schemes for partial membership being considered for Ukraine, such as Friedrich Merz’s plan for ‘associate membership’. But the UK will also have to be flexible, notably by accepting greater mobility of people, perhaps similar to Switzerland’s free movement of labour for the economically active, combined with an emergency brake if the numbers surge.
In the long run, the British may well find it frustrating to have to follow EU rules on parts
of the economy over which they have no formal say. That could increase support for rejoining. But membership will only become a serious option when there is a national consensus that the UK is better off inside the EU. The sooner pro-EU politicians find the courage to make the case for rejoining, the sooner we will reach that consensus.
Charles Grant is director of the Centre for European Reform.
Ten years after the 2016 referendum, Brexit has reshaped Britain but not settled its place in Europe. This collection of short essays brings together leading analysts, former politicians and officials to examine what leaving the EU has meant for Britain, for the EU and for the relationship between them – and to ask what lies in the decade ahead.