Photo: Depositphotos
Following the first official summit between the UK and the European Union since the UK’s exit from the bloc in 2020, defence and security cooperation is taking on new importance. Against the backdrop of geopolitical challenges such as the war in Ukraine and growing global instability, Europe is seeking to strengthen its security architecture. Ed Arnold, Senior Fellow in European Security at the Royal United Services Institute (RUSI), in his analysis for RUSI Reflects, looks at the new UK-EU Security and Defence Partnership (SDP), assessing its implications for the continent.
Context of the summit: a new stage in relations
The 2025 summit was the first official dialogue of this level since Brexit. It marked a desire on both sides to move away from post-Brexit tensions and focus on common interests, particularly in the security sphere. The new SDP agreement, which was the central theme of the talks, is designed to create a framework for cooperation in key areas such as intelligence sharing, joint military exercises, cyber security and countering hybrid threats.
Ed Arnold notes that although the UK is no longer part of the EU, its role in European security remains irreplaceable. The United Kingdom has one of the most powerful armed forces in Europe, a developed intelligence network and nuclear capabilities. At the same time, the EU is actively developing its own defence initiatives, such as the Permanent Structured Cooperation (PESCO) and the European Defence Fund (EDF), which makes cooperation with the UK strategically important.
What does the Partnership for Security and Defence envisage?
The SDP is not a full-fledged defence alliance, but it establishes a structured framework for cooperation. Among the key elements of the agreement:
- Jointly countering threats: The partnership involves closer coordination in the fight against cyber-attacks, disinformation and other hybrid threats that pose a common challenge to the UK and the EU.
- Military cooperation: The agreement facilitates the UK’s participation in PESCO projects on a selective basis, as well as joint military exercises, which increases interoperability of forces.
- Intelligence sharing: Enhanced cooperation between UK intelligence services and EU agencies such as Frontex or Europol to counter terrorism and organised crime.
- Innovations in defence: Working together on advanced technologies such as artificial intelligence in the military and the development of new weapons systems.
Arnold emphasises that the SDP is a compromise: The UK wants to retain its autonomy in foreign policy, while the EU wants to avoid becoming overly dependent on the US-dominated NATO. However, both sides recognise that without close cooperation, European security will remain vulnerable.
Challenges and prospects
Despite the positive momentum, the Partnership faces a number of challenges. First, political differences between London and Brussels, particularly on trade issues, may complicate the implementation of the agreement. Secondly, some EU countries, such as France, are in favour of greater strategic autonomy for Europe, which may contradict deeper cooperation with the UK, which is closely linked to NATO and the US.
Furthermore, the war in Ukraine and its implications for European security underscore the need for swift and coordinated action. The SDP could provide a platform for joint support for Ukraine, including through arms supplies, military training and sanctions against Russia.
Significance for Ukraine
For Ukraine, the new UK-EU agreement is a positive signal. The UK remains one of Kyiv’s key allies, providing significant military and financial support. A common position of the UK and EU within the SDP could increase pressure on Russia and facilitate greater coordination in the supply of weapons and humanitarian aid. Strengthening European security also creates more favourable conditions for Ukraine in its fight against aggression.
The UK-EU security and defence partnership is an important step towards strengthening European security in the face of global instability. Although the agreement does not resolve all differences between the parties, it provides a framework for cooperation in key areas, from cyber security to military innovation. For Ukraine, the SDP opens up new opportunities for cooperation with Europe, contributing to regional stability and countering common threats.
In his analysis, Ed Arnold emphasises: “European security is a shared responsibility. The SDP is not the end goal, but the beginning of a new phase where the UK and the EU are learning to work together for the common good.” In a rapidly changing world, this dialogue is critical for all who seek peace and security.
Source: RUSI Reflects: Are the UK and EU Aligned on Defence and Security?
Author: Aleksandr Potetiuiev
