Re-arming Europe: Strengthening EU-UK defence co-operation

Europe faces its most serious security crisis in decades. Russia’s full-scale invasion of Ukraine has broken post-Cold War assumptions about stability on the continent, while growing instability in Europe’s southern and eastern periphery poses additional threats. China is increasingly seen as a strategic competitor as well as a trading partner. At the same time, uncertainty over the US’ commitment to NATO, compounded by its shifting strategic focus toward the Indo-Pacific, has forced European states to reconsider their approach to defence and security. The case for greater European defence co-operation —both within the European Union and beyond — has never been stronger.

For the United Kingdom, this presents both an opportunity and a challenge. Notwithstanding Brexit, the UK remains one of Europe’s leading defence powers, with advanced capabilities in maritime, air, cyber, and intelligence operations, and a strong defence industrial base. As European security dynamics evolve, there is growing political momentum for closer EU-UK security and defence co-operation on both sides. The UK’s new Labour government is seeking a more structured partnership with the EU through the negotiation of a Security and Defence Partnership, part of a broader reset in EU-UK relations.

However, significant challenges remain. Institutional obstacles, particular national interests, political sensitivities, and long-standing differences over the EU’s defence-industrial policies risk limiting the scope of co-operation. The question is not whether closer co-operation is desirable, but how it can be achieved, and how it can best be structured to deliver tangible security and industrial benefits for both sides, on a time-scale that reflects the gravity of the current crisis.

This paper examines the future of EU-UK defence co-operation in this complex and rapidly shifting landscape. It explores the current state of engagement, the evolving role of the EU in defence policy, and the potential benefits and barriers to closer collaboration. It also assesses the implications of wider geopolitical developments—particularly the role of the United States and NATO — on the future EU-UK defence relationship. Finally, it considers the strategic, political, and industrial implications of deepening defence co-operation, outlining the choices and trade-offs facing both the UK and the EU.