Five years after the United Kingdom officially left the European Union, the Labour Party announced in its 2024 election manifesto its intention to ‘reset’ the country's relationship with the European Union, while ruling out a return to the single market or customs union or making concessions on freedom of movement. Despite these red lines, the new dynamic aims to overcome the mistrust and tensions associated with the period of negotiations and the immediate post-Brexit period and to pave the way for renewed cooperation in areas such as trade, security and defence.

Within the EU, the UK's desire to rekindle relations has been welcomed, provided that discussions do not undermine the implementation of existing agreement: the withdrawal agreement and the trade and cooperation agreement. The principle of a bilateral summit was agreed in October 2024, but without any specific objectives being defined. Indeed, this summit, which was held in the United Kingdom on 19 May 2025, is a step in a process of reviving relations that began even before Labour came to office in 2024. While it is an important milestone, this summit should not be seen as the ‘reset’ desired by Keir Starmer. Rather, its aim is to clarify the path taken by Brexit, which, far from being a past event, continues to be a long process of redefining the relationship between the European Union and a former member state.

The governance of EU-UK relations

From a formal point of view, relations between the European Union and the United Kingdom are currently governed by a set of treaties and mechanisms negotiated in the years following the 2016 referendum.

The 2020 Withdrawal Agreement sets out the terms of the United Kingdom's withdrawal, in accordance with Article 50 of the Treaty on European Union (TEU). The main elements of this agreement concern citizens' rights (protection of British citizens residing in the EU and EU citizens in the UK), the financial settlement (the UK's financial obligations to the EU) and specific provisions on the border on the island of Ireland. The Withdrawal Agreement introduced a Joint Committee responsible for supervising its implementation. The Joint Committee meets at the initiative of either party, or at least once a year. The last meeting, the fourteenth since 2020, took place on 29 April 2025. The Withdrawal Agreement also established six specialised committees on: citizens' rights; other provisions relating to the separation; issues relating to the implementation of the Protocol on Ireland and Northern Ireland; issues relating to the implementation of the Protocol on the Sovereign Base and Port Areas in Cyprus; issues relating to the implementation of the Protocol on Gibraltar; and financial provisions. The frequency of meetings of these specialised committees varies, with the two most frequently convened committees being the Committee on Citizens' Rights (fifteen meetings since 2020) and the Committee on Issues Related to the Implementation of the Protocol on Ireland and Northern Ireland, replaced by the Committee on Issues Relating to the Implementation of the Windsor Framework in 2023 (eight meetings since 2023). In cases where the Joint Committee is unable to resolve a dispute, the agreement provides for an arbitration procedure.

The 2021 Trade and Cooperation Agreement governs relations between the European Union and the United Kingdom. It sets out the rules for trade between the two parties, while ensuring that conditions of fair competition and respect for fundamental rights are guaranteed. The main governance body set up by the agreement is the Partnership Council, to which are added the Trade Partnership Committee and ten specialised trade committees, as well as eight specialised committees responsible for energy, air transport, aviation safety, road transport, social security coordination, fisheries, police and judicial cooperation, and participation in EU programmes. In addition, the TCA established four working groups to assist the specialised committees. More generally, it provided for the creation of a Parliamentary Partnership Assembly (PPA) comprising members of the European Parliament and the House of Commons, which meets twice a year. Finally, like the Withdrawal Agreement, the TCA provides for a complex dispute settlement system, including the establishment of an arbitration tribunal.

The two agreements provide for new governance frameworks to establish lasting cooperation between the European Union and the United Kingdom. The two sides meet regularly in the committees set up by the agreements, and as such, the relationship with the United Kingdom is unlike any other relationship the European Union has with a third country. That is why, from the Union's point of view, the priority must remain the fulfilment of the commitments made under the 2020-2021 agreements above all other objectives. Indeed, their implementation has not been without challenges. As early as 2020, Boris Johnson's government had proposed a bill the Internal Market Act, which, in its first version, included elements that infringed international law since it was in contradiction with the Withdrawal Agreement and in particular with the Protocol on Northern Ireland. This attitude significantly damaged the UK's international reputation and contributed to undermining the trust that the European Union was prepared to place in it after Brexit.

Rebuilding the relationship: a slow process

The aspiration to revive the relationship is not new and is certainly not the preserve of the current Labour government. Despite the mistrust that largely characterised relations with the Johnson government during and immediately after the negotiations on the Withdrawal Agreement and the TCA, it was also during its term of office that the first signs of a commitment to allowing the United Kingdom the opportunity to move closer to the European Union became apparent.

Russia's invasion of Ukraine in February 2022 was a key factor in this initial rapprochement. The invitation to Liz Truss, then British Foreign Secretary, to join the Extraordinary Foreign Affairs Council of 4 March 2022, demonstrated Europe's readiness to involve the United Kingdom from the outset in discussions on how to respond to the situation in Ukraine. Since then, the United Kingdom has continued to play a leading role in supporting Ukraine and is working with France to build a ‘coalition of the willing’ to help secure peace. The joint trip made by the British, French, German and Polish leaders to Kyiv on 10 May confirms the strength of the UK's relationship with its closest allies in Europe on the security of the continent. Moreover, the coordination of sanctions against Russian interests has strengthened their impact and demonstrated the ability of the United Kingdom and the European Union to work together in an area not covered by the 2020 and 2021 treaties. The success of this cooperation could serve as a model for other areas of the bilateral relationship. Furthermore, Liz Truss, who (briefly) became Prime Minister following Boris Johnson's resignation, attended the first summit of the European Political Community, where she emphasised the need to ‘work with Europe’.

However, relations between the European Union and the United Kingdom continued to be marked by difficulties related to the implementation of the Protocol on Ireland and Northern Ireland until Rishi Sunak, who became Prime Minister on 25 October 2022, opened the possibility of negotiating a new agreement. The Windsor Framework, signed in February 2023, provided practical solutions to the problems posed by new customs and trade regulations affecting the island of Ireland. This legal and administrative breakthrough was particularly noted for its political implications. On the British side, the signature was a way for the Conservative government to demonstrate that it was no longer powerless in the face of the difficulties caused by Brexit in Northern Ireland and, incidentally, to make people forget Boris Johnson's attempt to violate international law. The revival of relations with the European Union did not stop there, as Rishi Sunak's government negotiated the UK’s return to the Horizon Europe and Copernicus programmes in septembre 2023.

Thus, both the change in rhetoric and the wish to move closer to the European Union existed before Labour came to office. Nevertheless, the Sunak government's objectives were necessarily limited: it had to contend with a divided Conservative Party and a parliamentary majority largely responsible for the defiant attitude that had characterised bilateral relations during Boris Johnson's term in office. Furthermore, if he wanted to have any chance of staying in power, Rishi Sunak had to avoid dwelling on the issue of relations with the European Union, which remained a source of division among the electorate. Conversely, it was not in the European Union's interest to invest too much in the relationship with a government that was expected to lose the 2024 general election.

The Starmer government's ambitions constrained

Shortly after arriving at 10 Downing Street in July 2024, Keir Starmer indicated that responsibility for the United Kingdom's relations with the European Union would be transferred from the Foreign Office to the Cabinet Office, under the direct responsibility of the Prime Minister. It was therefore Nick Thomas-Symonds, Minister for the Cabinet Office, the Constitution and the European Union, rather than the Foreign Secretary, who was tasked with negotiating with the team led by Maroš Šefčovič, Vice-President of the European Commission. This choice indicated the priority given by the Prime Minister to ‘resetting’ relations with the European Union.

However, despite the use of ambitious rhetoric, the government's objectives were immediately limited by the announcement of red lines on the single market, the customs union and free movement. These limitations can be explained primarily by the political situation in which Labour finds itself at the national level. Admittedly, the party won a majority of 411 seats in the general election on 4 July 2024, compared with 121 for the Conservatives. But this large majority in Parliament does not reflect the reality of a fragmented electorate that has also turned to other parties such as Reform UK, a pro-Brexit and anti-immigration party. The party won only five seats in Parliament, including that of its leader, Nigel Farage, but with more than 4 million votes and 14.3% of the vote, Reform UK established itself as the third force at national level, coming second in 98 constituencies (in 89 cases behind Labour). On 1 May, Reform UK confirmed its influence on British politics by winning an additional seat in Parliament in a by-election and significantly improving its results in local elections in England, where it took control of ten local authorities. Nigel Farage's party has consolidated its ability to influence the debate, and its increased media presence allows it to position itself as the guardian of Brexit by denouncing anything it sees as a betrayal of the country's independence. Reform UK's intransigence on the issue of relations with the European Union has direct consequences for the Conservative Party, which needs to rebuild itself after its defeat in the 2024 elections, taking into account the trajectory of its traditional electorate, which has shifted to the far-right party. Pressure from the staunchest Brexit supporters is also being exerted on the Labour majority, which, in the hope of protecting its future at the polls, has avoided giving European issues a central place in its strategy and discourse.

By continuing to rule out any future return as a member of the European Union, likewise a return to the Single Market or considering the freedom of movement, Keir Starmer is primarily seeking to avoid reopening the debate on Brexit and its consequences, which still divides British society. Participation in the single market, based on the model of the European Economic Area countries that are not members of the European Union (Iceland, Liechtenstein and Norway), has been ruled out because it involves the free movement of goods, capital, services and people. And the free movement of people, which is linked to the immigration debate, is seen as unacceptable by some voters. The potentially inflammatory nature of anything to do with immigration explains why the UK initially rejected the EU's mobility plan for young people, even though this does not entail free movement. It is more surprising that a government that is focused on economic growth has ruled out discussing a possible return to the customs union. Here again, despite the benefits that a return to the customs union could bring to the British economy through the simplification of trade in goods, the United Kingdom is not prepared to accept the principle of even partial alignment of certain standards with those of the European Union, nor to give up the possibility of negotiating bilateral trade agreements. The announcement of the signature of an agreement with the USA on 8 May confirms that the UK's commercial strategy is now being written independently of that of the European Union.

Relaunching cooperation with the EU-27

While Brexit does indeed mean leaving the European Union and the withdrawal of the United Kingdom from European institutions, it has not always led to the de-Europeanisation of British policies. This is particularly true in the field of foreign policy, where the United Kingdom has actively sought to continue coordinating its approach with that of Member States, as evidenced by the significant number of bilateral declarations signed since 2021. In addition, alongside the revival of relations with the European Union, bilateral relations with Member States have been characterised by a desire for appeasement and cooperation in specific areas.

Franco-British relations have thus undergone a period of intense tension, exacerbated by disputes over fishing, customs controls at the border and the management of migrants in Calais. Furthermore, these relations were deeply affected by the crisis triggered by the signature of the AUKUS agreements in September 2021. But a turning point came in March 2023 with a bilateral summit in Paris, during which President Emmanuel Macron and Prime Minister Rishi Sunak demonstrated a clear resolve to make a “new start”. An ambitious joint declaration was signed, setting objectives in eight areas as varied as cooperation on Ukraine, the European Political Community (the country hosted the fourth summit in July 2024), defence and security, the fight against organised crime, cyber threats and terrorism, foreign policy and global issues, energy and decarbonisation, irregular migration, and economic and social ties. A new bilateral summit is planned for 2025 to take stock of the objectives set in 2023 and to discuss, in particular, the opportunity to relaunch bilateral cooperation within the framework of the Lancaster House Agreements, signed in 2010. The summit is being prepared against a backdrop of enhanced cooperation between France and the United Kingdom on a proposed reassurance force in Ukraine.

Germany is another key partner in Europe. The UK and German economies are closely linked, which has led the two countries to move quickly to ease trade tensions and strengthen bilateral partnerships, notably in terms of energy. The Trinity House Agreement, signed in October 2024, aims to strengthen German-British cooperation in the field of defence. It is the first part of a broader agreement that is expected to cover other areas such as foreign policy, justice and law enforcement, economic growth, resilience, science and technology, energy and climate, and the environment. Negotiations on this treaty were suspended during the German election campaign, but Friedrich Merz's new government is expected to finalise it with the Starmer government.

But while France and Germany are the UK's main partners in Europe, the country has sought to strengthen its ties with other countries. For example, cooperation with Poland has intensified, based on a shared vision of security issues in Eastern Europe. This cooperation will take the form of a Defence and Security treaty in 2025. The UK also signed a Memorandum of Understanding with Italy in 2023 and has since strengthened its cooperation, particularly with regard to immigration and the fight against networks and trafficking. The two countries cooperate in the military industry sector, with the 6th generation fighter aircraft programme GCAP (Global Combat Air Programme). These few examples show that cooperation with Member States has never stopped, despite the UK's departure from the European Union. On the contrary, bilateral ties are an essential aspect of the Europeanisation of the United Kingdom, and the revival of cooperation with the European Union is now an additional and complementary aspect of the dynamic that already exists between the United Kingdom and the EU-27.

The 19 May summit: towards greater cooperation

On the British side, the objectives for reviving relations with the European Union are organised around three pillars: foreign and security policy; the safety of citizens, with enhanced cooperation between police forces and the fight against serious and organised crime, such as counter-terrorism operations and the fight against illegal immigration; and, finally, growth and trade, with the negotiation of a new sanitary and phytosanitary (SPS) agreement and the improvement of provisions on the mutual recognition of professional qualifications and provisions for touring artists.

For its part, the European Union does not wish to make any substantial changes to the TCA, with which it says it is satisfied. Its only expectation is the full implementation of the 2020 and 2021 agreements, in particular the provisions on trade between the United Kingdom and Northern Ireland, in accordance with the Windsor Framework, and on the protection of the rights of European Union citizens residing in the United Kingdom. During the Brexit negotiations, the European Union regretted the decision of the British government at the time to drop the defence and security chapter. Furthermore, in 2024, at the time of the UK elections, the Commission sought to open negotiations on a youth mobility scheme. Finally, more recently, some Member States, including France, have argued for the need for a long-term agreement on fishing rights, as the current ‘transition’ period contained in the TCA was bound to end in June 2026. Despite the relative economic importance of fishing, such an agreement was viewed as a prerequisite for the signing of a comprehensive agreement with the United Kingdom. On 19 May, the UK and the European Union agreed to renew the current deal until 2038.

Despite its initial reluctance regarding a mobility scheme for young people, the British government now seems ready to sign a ‘sensible’ agreement with the European Union, which would allow young people aged 18 to 30 to travel and work freely for a limited period. In the field of energy and climate, the UK and the EU have committed to reduce friction in the electricity trade and aim to ensure that the United Kingdom and the European Union do not impose carbon adjustment taxes on each other at their borders.

Negotiations on a possible SPS agreement, which would reduce controls on trade in agri-food products, have taken place. Such an agreement has been included as an objective in the renewed agenda for cooperation between the European Union and the United Kingdom, which both sides adopted on 19 May. This would reduce tensions on trade between Great Britain and Northern Ireland, which already generally follows EU SPS regulations. Furthermore, it would be relatively simple to implement, as the UK as a whole has rarely deviated from EU regulations. However, the EU could insist on ‘dynamic alignment’ and the ultimate supervision of the agreement by the European Court of Justice, which would inevitably spark debate in the UK about betraying Brexit.

Given the international context, particularly the war in Ukraine and uncertainties surrounding Donald Trump's attitude towards security in Europe, the United Kingdom and the European Union have signed a ‘security and defence partnership’. The scope of this agreement was debated, since it involved authorising, or not, the United Kingdom to join the European Defence Agency (EDA), — according to the agreement, ‘the possibilities to establish an administrative arrangement between the United Kingdom and the EDA will be explored’ — to have access to procurement financed by the SAFE programme (Security Action for Europe), or participate in European Union military operations (under the CSDP), which the agreement provides for. The European Union has already signed security and defence agreements with six third countries (Albania, South Korea, Japan, North Macedonia, Moldova and Norway) and nineteen partners contribute to CSDP missions and operations through framework agreements. The UK's participation in European programmes would therefore be based on precedent and would not constitute an exception, even if the country's international status – as a permanent member of the UN Security Council, a member of NATO and the G7, and a nuclear power – is not comparable to that of other third countries. This status is both an asset for Europe, encouraging Member States to maintain strong bilateral ties with the United Kingdom, but also a challenge, particularly regarding potential competition from British companies in the defence industry.

Thus, beyond security and defence, the 19 May summit especially led to the announcement of more detailed negotiations on a wide range of issues. The shared objectives of both sides, as well as their respective constraints, were the focus of a declaration accompanied by a provisional timetable for future agreements on a sector-by-sector basis. 

***

One of the main benefits of this summit has been to confirm the commitment of both parties to improve cooperation within an official institutional framework. However, at this stage, the red lines drawn by the government and the European Union's lack of appetite for renegotiating the TCA – or certain aspects of it – make it difficult to envisage any profound change in relations.