Our report argues that the UK–EU Security and Defence Pact agreed in May 2025 is a necessary and overdue rebuilding of political and operational ties, but that it is not yet scaled to match the gravity of Europe’s security environment. The pact usefully codifies cooperation that had already developed informally since Russia’s 2022 invasion, establishes regular high-level and working-level dialogue, and creates a platform for coordination on sanctions, training missions, military mobility and wider geopolitical issues. It marks a clear strategic reset after the post-Brexit vacuum and helps restore predictability and trust between the UK and the EU.

Our analysis also highlights the limits of the agreement and sets out where greater ambition is needed. The pact does not grant the UK access to major EU defence-industrial instruments such as SAFE or the European Defence Fund, nor does it integrate the UK into EU capability planning or operational decision-making. At a moment when Russia is gaining ground and the US is signalling a reduced willingness to underwrite European security, Europe needs rapid progress on joint procurement, industrial-scale production for Ukraine, deeper intelligence and planning coordination, and a coherent continent-wide defence strategy. The UK–EU pact is an important first step; the challenge now is to use it as a platform for the level of integration that today’s threats require.