Written by: Vittoria Montinari
Supervised by: Philip Sääw
Edited by: Cesar Arnold
The EU-UK summit, held on May 19th at Lancaster House in London, marked a decisive moment in post-Brexit European politics. As the first formal summit since the UK’s departure from the European Union, the meeting brought together key EU officials, namely European Council President António Costa, European Commission President Ursula von der Leyen, and High Representative Kaja Kallas, alongside UK Prime Minister Keir Starmer (Tocci, 2025). Amidst a backdrop of global geopolitical turmoil, the summit symbolised a renewed commitment to security and defence cooperation.
Russia’s ongoing aggression in Ukraine, growing far-right threats within the EU, and volatile US security engagements in Europe render a unified response necessary. The timing of the summit emphasises the urgency of tighter EU-UK bonds against shared existential threats to the continent (Tocci, 2025). During a joint press conference, António Costa remarked that the agreements represent “a new chapter in the relationship”, adding that deeper cooperation “is not a luxury. It is a necessity” (European Council, 2025b, paras. 4-5).
The centrepiece of the gathering was the signing of the EU-UK Security and Defence Partnership (SDP), reaffirming the interdependence and like-mindedness of the two actors, sharing similar values and interests in the defence framework (European Council, 2025c). Building on the 2020 Withdrawal Agreement and the 2021 Trade and Cooperation Agreement (Harrois, 2025), the SDP was envisioned to create efficient mechanisms for security dialogue and strategic alignment (European Council, 2025a). The agreement formalises cooperation on a broad range of security challenges, including cybersecurity, hybrid threats, critical infrastructure protection, and the use of emerging technologies such as AI (European Council, 2025c). It also sets up semi-annual foreign and security policy dialogues, an annual high-level defence forum, and the UK’s participation in the Schuman Security and Defence Forum to deepen cooperation in peacebuilding, crisis management, and military mobility under PESCO.
However, debate and concern still surround the SDP. While it provides a useful procedural framework, critics say it lacks “tangible deliverables or milestones, instead relying on vague commitments”, ultimately making the partnership more symbolic than strategic (Arnold, 2025, para. 6). One major point of discussion has been potential UK involvement in the EU’s €150 billion SAFE defence fund (Harrois, 2025). While the partnership opens the door for British firms to participate in joint procurement projects, it remains vague regarding access to funding (De La Feld, 2025). Further bilateral negotiations will be necessary to clarify such points and avoid treating the UK as “simply another third country” dealing with the EU (Arnold, 2025, para. 8).
This vagueness represents a missed opportunity. Failing to include firm commitments on defence cooperation undermines the SDP’s military ambitions, especially given the need to strengthen European industrial capacity amidst Russian aggression (Whitman, 2025). Although the agreement reflects a normalisation of EU-UK relations it stops short of a strategic breakthrough, focusing more on “formalising existing ad hoc cooperation” (Whitman, 2025, para. 8). The summit thus marks a modest beginning, with tangible progress depending on sustained political will and long-term efforts (Arnold, 2025).
The 2025 EU-UK summit can be summarised as a meaningful but cautious step towards restoring relations between two natural allies. Crucially, the UK’s Labour government signalled its willingness to depart from the adversarial Brexit years by participating in this meeting (Elgot & Stacey, 2025). Despite ongoing domestic scepticism and political fragmentation in Parliament, Prime Minister Keir Starmer’s administration “has invested considerable effort” to restore productive relations with Brussels (Chatham House, 2025, para. 1). Furthermore, while the agreements may appear more procedural than transformative (Arnold, 2025), they lay the groundwork for deeper cooperation across strategic domains. In a rapidly evolving geopolitical landscape, the significance of structured security dialogue and institutionalised trust between the UK and EU cannot be overstated. Whether these initial steps evolve into a robust trans-European partnership remains to be seen, but the journey has begun, proving that “the UK has left the EU, but it has not left Europe” (Tocci, 2025, para. 12).
Bibliography
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