Why Brexit still haunts British politics

Perhaps most strikingly, Wes Streeting, until recently health minister and, since his resignation, a vocal critic of Prime Minister Keir Starmer, recently said that leaving the European Union was a “catastrophic mistake” and went on to say that Britain’s future lies in the within Europe. This sparked outrage among Brexit supporters and a wave of speculation that a new leader could take a far more ambitious approach to relations with the EU.

But both the outrage and the speculation overlook key logistical questions. Among these: where is the United Kingdom in its relations with the EU? What would it take for the United Kingdom to rejoin the Union? And if that were the case, how could the EU react?

The beginnings of Brexit

To understand the UK’s turnaround towards the EU, it is necessary to briefly retrace the path that led to this moment. After the referendum of June 23, 2016 and a long transition period, Brexit officially came into force in January 2020. The United Kingdom finally left the single market just a year later, after negotiating the Trade and Cooperation Agreement (TCA), which remains to this day the legal basis for most aspects of bilateral relations.

Despite bold promises by successive Conservative governments to boost growth by removing large swaths of EU law, many of these provisions still feature in British law. Furthermore, the United Kingdom has failed to take advantage of its new regulatory autonomy, except in certain limited areas (notably financial services). Then Keir Starmer’s Labor government came to power pledging to fix “Boris Johnson’s botched Brexit deal” and dismantle the trade barriers it had erected.

This is how what was called the “reset” began, with the new government setting out to modify the agreement signed by the former Prime Minister. But these modifications had their limits. The Labor Party has not called into question the underlying principles of the Trade and Cooperation Agreement (TCA): the rejection of a customs union, membership of the EU single market and the free movement of people.

At the UK-EU summit held in May 2025, the two parties agreed on a negotiating agenda focused on agriculture, the interconnection of their respective emissions trading systems, possible participation of the United Kingdom in the internal electricity market of the EU and a mobility program for young people. They also pledged to collaborate more closely on security, so Donald Trump worked to undermine the assumptions on which Europeans had based their thinking about security since World War II.

More than a year after this summit, there is not much to celebrate. The French can rejoice: they have obtained a 12-year extension of the fisheries agreement, which is more than they had initially requested. Aside from that, there has been very little tangible progress and some notable setbacks. Chief among these is the breakdown of negotiations on the United Kingdom’s participation in the “Security Action for Europe” (SAFE) program, intended to accelerate joint defense purchases. The cost of 150 billion euros attributed to this program by the EU pushed the United Kingdom to withdraw from the negotiations, thus revealing the meaninglessness of the beautiful rhetoric on the vital importance of common security interests.

For the rest, negotiations are continuing on technical areas intended for strengthened cooperation. Some predictable points of contention have emerged, notably over the extent of the issues on which the EU expects the UK to align with its laws (without having a say in the content of those laws). Furthermore, discussions on youth mobility appear to have been bogged down by the UK’s proposed cap, which is unacceptable, but also by the EU’s requirement that European students studying at UK universities be able to pay ‘domestic’ (much lower) tuition fees, of around £9,500 (€11,000), rather than the almost £60,000 (€70,000) that some international students pay when studying in the UK.

The ambiguity surrounding plans for a second UK-EU summit is testimony to the bad turn of events. The intention, at least on the British side, was that this summit would be an opportunity to announce the agreements reached and to define a program for future cooperation. The fact that a meeting initially planned for May, then June, is now only provisionally scheduled for July says a lot about the current chances of progress.

This is where a crucial asymmetry clearly appears. The UK government is desperate to make progress in removing trade barriers. So much so that, dissatisfied with the current negotiations, he explicitly made it known that he wanted to go further. Yet the EU, for its part, does not share London’s sense of urgency. Agreements on agriculture or electricity matter much less to European policy makers than to their British counterparts. On the EU side, we are ready to take economic negotiations hostage to advance discussions on youth mobility. Then, following the disastrous results of the Labor Party in the local elections in May, a leadership race broke out in the big day. Wes Streeting ensured that relations with the EU would be a key part of the debate. In doing so, he has sparked a wave of speculation that the UK is preparing for a radical change in its approach to the EU, or even considering applying to rejoin the Union.

Will the UK try to rejoin the EU?

So what should we think of all this? On the one hand, Wes Streeting’s comments must be taken with a certain caution. Partly because he didn’t actually say anything at all. He barely specified what the “special relationship” he called for with the EU would entail. And rejoining the EU “one day” is hardly a firm political commitment. It should also be kept in mind that Wes Streeting has been able to capitalize on his bold but vague statements. He is widely tipped as a candidate for leadership of the Labor Party if an election were to take place. And it is the members of the Labor Party who will ultimately decide the identity of the new leader of the Labor Party, and therefore the new British Prime Minister. The general population A recent poll suggests that 58% of all potential voters want to rejoin the EU, but an overwhelming 84% of Labor voters share this wish.

Consequently, candidates for party leadership will have to make a pro-European speech. At best, they will succeed, like Wes Streeting, in giving off a pro-European “impression” without committing to anything specific. At worst, they will be bound by promises they cannot keep. But these commitments should be received with a certain skepticism, because recent history clearly shows that promises made during elections at the head of a party are not necessarily kept. Moreover, while a possible leadership race has certainly enlivened the debate on relations with the EU, other factors, completely independent of Keir Starmer’s fragile hold on power, are conspiring to encourage Labor Party MPs to reconsider this relationship.

On the one hand, the economic repercussions of Brexit are the subject of broader discussions. The Chancellor of the Exchequer*, Rachel Reeves, was quick to highlight the economic estimate according to which Brexit would have had a negative impact of 8% on British GDP. But even if the UK got everything it wanted from the reset negotiations currently underway, the measures under discussion would, according to the government’s own forecasts, only contribute to growth well below 1%. Desperate to revive growth seen as the key to their re-election in 2029, Labor MPs are now wondering whether closer ties with the EU could be a way to achieve this.

Second, changes in global politics have led some on the left to conclude that the UK should move even closer to its European neighbors. As President Trump undermines the security guarantee offered by the United States, Europeans clearly have an interest in seeking greater security autonomy. More broadly, in a world where the US is seen as increasingly unreliable, some Labor MPs are wondering whether the UK should take a more “European” approach to regulation in areas such as AI, rather than straying from the EU rules in a bid to attract US investment.

Finally, there is politics. Since the 2024 election, Labor has lost a number of voters to parties on the liberal left of the political spectrum, from the Greens and Liberal Democrats, to Plaid Cymru in Wales and the SNP in Scotland. As a result, the party lost more Remain supporters than Leave supporters, in a context where Brexit itself is losing popularity with the British public. Therefore, winning back these voters and trying to unite progressive voters under the Labor banner is a top priority. This is prompting some party members, such as Keir Starmer himself, to suggest that an “ambitious” approach to relations with the EU could be one way to achieve this.

For a variety of reasons, discussions are therefore taking place within the ruling party about whether more can be done to rebuild the UK’s relationship with the EU. But what would a more “ambitious” program mean? This is where things get complicated. We know what the UK wants. London is willing to consider using alignment to guarantee market access in sectors other than those currently under negotiation.

The problem is that the EU is not necessarily willing to make this concession. From Brussels’ perspective, the UK is trying to reap the benefits of the single market without committing to its obligations, including large financial payments and the free movement of people. European leaders are therefore making it increasingly clear that the UK should choose one of the many relationship models created for other countries, rather than hoping for a tailor-made deal.

Generally speaking, three models are available to him. The UK could negotiate a customs union with the EU. Or it could join the single market. None of these options are without major problems. The first would deprive London of the ability to negotiate its own trade agreements and would in any case have only a relatively small economic impact. The second option would certainly have a significant economic impact, but it would commit the United Kingdom to adopting EU rules on which it has no say for the whole economy, while paying large sums for this privilege and re-accepting free movement. This leaves the third option: the United Kingdom could decide to rejoin the European Union. Some Labor Party members are privately suggesting that the party should make “reintegration” its main election promise before the next election. Others are appalled by the idea. The outcome of the debate will depend on many factors, including the identity of the new Prime Minister. What is clear is that the debate is intensifying and relations with the EU are once again becoming a central topic, at least within the ruling party.

How will the EU react?

If the UK does indeed choose to embark on the path of re-entry into the EU, the question changes. What does the EU think of all this? And what will the cost be to the UK? Relations with the United Kingdom are in fact not a priority for Brussels as they are for the British government. Therefore, the EU will ensure that it benefits from any agreement reached. We have already seen this dynamic with the financial demands placed on the UK when it attempted to join SAFE. We also saw it in the payment of more than 500 million pounds by the British government to participate for a year in the EU student exchange program, Erasmus+.

Finally, the EU will lead tough negotiations to encourage others. In other words, it will ensure that the UK accepts obligations while gaining rights, in order to highlight the benefits of membership to other countries who might consider weakening the bloc. Many member state governments face populist movements that say the EU is too powerful and interferes too much in national life. Granting the UK a form of tailored access to the single market could prompt member states to demand special treatment. Then there is Switzerland, which has just concluded a renegotiation of its agreement with the EU and which will closely follow the negotiations with the United Kingdom to ensure that London does not obtain anything that was refused in Bern.

Hence the insistence that the United Kingdom, if it wishes to go further, choose one of the established options available to it. If the UK joined the single market, the EU would be able to adopt regulations binding on a G7 economy which would have no official say over their content. Whether such an arrangement would stand up to British politics and the British media, known for its outspokenness, is another question entirely. From Brussels’ point of view, however, seeing the only member state to have ever left the club return with an outstretched hand to demand reinstatement would be a real political triumph.

The UK’s ruling party is considering its relationship with the EU. And as always, all possible choices involve difficult trade-offs. The status quo has an economic cost. Membership of the single market without membership of the EU would significantly limit British autonomy. Rejoining would require difficult negotiations on the conditions of reintegration and, undoubtedly, a heated debate at the national level.

The United Kingdom’s choice will depend on the evolution of its internal political situation. First of all, the identity of the new Prime Minister. But also the debates within the Labor Party, the results of the polls, the evolution of public opinion and the capacity of the government to revive growth by other means.
Whatever the final decision, one thing is clear: ten years after the referendum that led to Brexit, Europe still haunts British politics.

*editor’s note: United Kingdom Government Minister for Finance and Treasury, Head of Her Majesty’s Treasury