Policy paper

Security and defence partnership between the European Union and the United Kingdom of Great Britain and Northern Ireland

Published 19 May 2025

1. The European Union (EU) and the United Kingdom of Great Britain and Northern Ireland (UK) face a volatile and increasingly challenging security environment in Europe and in its broader neighbourhood, as demonstrated by Russia’s unprovoked and unjustified war of aggression against Ukraine. Russia attempts to change unilaterally, by force, the internationally recognised borders of Ukraine and the security order in Europe. The UK and the EU have significant shared interests, adhere to international law, stand united to uphold and strengthen the rules-based international order, based on the purposes and principles of the United Nations Charter, and promote effective multilateralism with the United Nations at its core. The promotion and defence of universal values of respect for human dignity, freedom, democracy, equality, the rule of law, as well as human rights will continue to underpin the co-operation between the EU and the UK.

2. The UK and the EU share a responsibility for the security of Europe. The security and prosperity of the UK and the EU are also closely interconnected and interdependent. These shared interests go beyond traditional strategic domains, to include areas such as cyber and hybrid threats, space, and the resilience of critical infrastructure. The EU and the UK share the same challenging security environment and both have vital interests in the peace, security and stability of Europe and beyond. The UK and the EU are committed to strengthening their partnership in security and defence.

3. The relationship between the EU and the UK is underpinned by the Withdrawal Agreement (WA), including the Windsor Framework, and the Trade and Co-operation Agreement (TCA)^{[footnote 1]}. Under the TCA, Cyber and Counter-terrorism dialogues between the UK and the EU have been established.

4. The UK and the EU positions on foreign and security policy are closely aligned on many issues related to the global outlook and challenges, in the light of shared values including the promotion of democracy and commitment to upholding international law.

5. As a permanent member of the UN Security Council, a European NATO ally as well as a G7 and G20 Member, the UK is an essential partner for the EU in the area of peace, security and defence. The EU’s Common Security and Defence Policy (CSDP) and the UK’s action on security and defence can together make a significant contribution to shared objectives.

6. In the current security environment, for the EU, the mutually reinforcing strategic partnership with NATO is essential for Euro-Atlantic security. For the UK and 23 EU Member States that are also NATO allies, the Atlantic Alliance remains the foundation of their collective defence. The EU-UK Security and Defence Partnership will reinforce the European contribution to NATO.

7. The Agreement between the European Union and the United Kingdom of Great Britain and Northern Ireland concerning security procedures for exchanging and protecting classified information (“Security of Information Agreement”) was concluded in 2020.

8. The UK has also applied to join the Permanent Structured Co-operation on security and defence (PESCO) project Military Mobility which was authorised by the Council on 14 November 2022.

9. The EU and the UK are closely aligned in their support to Ukraine, notably through the Ukraine Defense Contact Group (UDCG), including the EU Military Assistance Mission (EUMAM) and the UK Operation INTERFLEX, in the context of their broader co-operation on civil reconstruction, financial support and sanctions policy. The co-operation between INTERFLEX and EUMAM for Ukraine has been instrumental, training more than 120 000 Ukrainian soldiers between them.

10. Our Civilian and Military Missions and Operations have cooperated closely from protecting freedom of navigation in the Red Sea, to maintaining security in the Western Balkans.

General framework

11. The seriousness of the challenges we face calls for ambitious security and defence dialogue and co-operation between the UK and the EU. In this context, the EU and the UK have decided to establish and implement a comprehensive, balanced and mutually beneficial Security and Defence Partnership that will frame their co-operation across the security and defence spectrum.

12. The Security and Defence Partnership will be based on dialogue and consultation mechanisms to facilitate the exchange of information, as well as steering and oversight of its implementation while ensuring the respective roles of the Council and the High Representative of the European Union for Foreign Affairs and Security Policy (HR):

A. 6-monthly foreign and security policy dialogues between the HR and the UK Foreign and Defence Secretaries, to conduct and enable strategic consultations in thematic and geographic areas of joint interest such as Russia/Ukraine, Western Balkans, Indo-Pacific and hybrid threats.

B. The HR may, where appropriate, invite the UK regularly to EU high-level meetings, including at the Council as appropriate. The UK may, where appropriate, invite the HR regularly to high-level meetings organised by the UK.

C. A dedicated Security and Defence Dialogue between the UK and the EU takes place annually, between the European External Action Service (EEAS) Deputy Secretary General with relevant Ministers or Permanent Secretaries of the UK Foreign Commonwealth and Development Office (FCDO) and the UK Ministry of Defence. The EU and the UK will make full use of this Security and Defence Dialogue to monitor the implementation of the Security and Defence Partnership and provide further guidance as appropriate.

D. Annual working level consultations will prepare the Security and Defence Dialogue between the UK and the EU, as well as ensure follow up to the guidance set by the Security and Defence Dialogue.

E. Thematic dialogues will be conducted as provided for in and on the basis of provisions in the TCA, notably in the areas of cyber issues; counter-terrorism; and countering proliferation of weapons of mass destruction, small arms and light weapons, other conventional weapons and arms exports control.

F. The HR will invite the UK to participate in the biannual Schuman Security and Defence Forum, together with key partners of the EU.

Areas of co-operation

13. Within the general framework established by the Security and Defence Partnership, the EU and the UK will maintain flexible and scalable engagement between relevant officials on areas of shared interest and aim to expand their co-operation including in the following areas:

Exchanges on regional security issues

14. In the light of shared foreign and security policy interests, the UK and the EU will hold regular exchanges on security issues of common interest. The EU and the UK will strengthen and enhance their collaboration in support of Ukraine. The UK and the EU will explore opportunities to engage and collaborate further on other priority regions as appropriate, such as Russia/Ukraine, the wider Eastern European Neighbourhood including the Black Sea, the Western Balkans, the Arctic, the Middle East, Africa, in particular the Horn of Africa and the Sahel, and the Indo-Pacific. In support of common objectives, the EU and the UK will continue to cooperate in the area of sanctions.

Peace building and crisis management

15. The EU and the UK will establish a dialogue on peace mediation, conflict prevention, stabilisation and resolution, and crisis management. The UK and the EU will explore co-operation in these areas, including co-operation in the field of CSDP, joint support to third states, sharing of best practices, and joint training.

16. The UK and the EU will enhance their coordination on shared priorities in peace mediation, conflict prevention, and crisis management in multilateral fora, notably in the UN context and in regional organisations as well.

17. The UK will consider its participation in the EU CSDP civilian and military crisis management, in geographical areas of common interest, upon the invitation of the EU. The EU and the UK will explore the arrangements which could enable such participation in line with the respective decision making procedures. The UK and the EU will explore possibilities for further military co-operation.

18. The UK will be invited to observe and/or participate in the EU crisis management exercises under CSDP and, the UK will invite the EU, including the EU Military Staff (EUMS), to observe and/or participate in relevant crisis management exercises as appropriate.

19. The UK and the EU will establish regular contacts between the EEAS Crisis Response Centre and the FCDO Crisis Management Department with a view to upscaling real time information exchange and coordination.

20. The EU and the UK will hold regular consultations and deepen coordination on consular matters affecting the safety and security of their citizens in third countries, in particular on consular crisis preparedness and response.

21. The UK and the EU will hold regular consultations on these subjects in the context of wider international disaster response. In that framework, the EU and the UK will explore co-operation between respective structures, including the EU’s Civil Protection Mechanism.

Maritime security

22. The EU and the UK will hold regular exchanges on maritime security, and explore ways to deepen practical co-operation with the aim of promoting a free and rules-based maritime security environment, including security and resilience of critical infrastructure, secure sea lines of communication and the protection of freedoms of navigation and overflight, as well as the peaceful settlement of disputes, in accordance with the United Nations Convention on the Law of the Sea.

23. The UK and the EU will enhance maritime security coordination and dialogue on the EU’s and the UK’s initiatives and programmes in the maritime domain, including joint activities at sea, noting the example of exchanges between the EUNAVFOR ASPIDES and Prosperity Guardian in the Red Sea, and exploring them also between other operations. The UK and the EU will regularly share information on respective maritime security capacity building initiatives in third countries.

24. The EU and UK will share information on the practices and operations of the shadow fleet, and coordinate their responses to the risks posed by its ships and facilitators to the environment, maritime safety and security, and the integrity of international trade.

Security and defence initiatives, policies and instruments

25. The EU and the UK will conduct regular exchanges on the development of respective security and defence initiatives, including on defence readiness and defence industry. The UK and the EU will explore possible mutual involvement in respective defence initiatives in accordance with the respective legal frameworks.

26. The UK and the EU are committed to strengthen co-operation to enhance military mobility, including: through the UK’s participation in the PESCO project Military Mobility, in accordance with the general conditions under which third States could exceptionally be invited to participate in individual PESCO projects; and the EU-NATO co-operation in this field, with a view to the swift and seamless movement of military personnel and materiel across Europe.

27. Possibilities for establishing an Administrative Arrangement between the UK and the European Defence Agency (EDA) will also be explored, in accordance with respective processes.

Space security

28. The EU and UK share a strategic interest in strengthening co-operation in the space domain in line with common objectives. The EU and the UK will therefore establish regular exchanges on space security to discuss inter alia threats and respective policy frameworks with a view to strengthening co-operation in areas of shared interest.

29. The UK and the EU, in close coordination with its Member States, will develop co-operation on space-related security issues, including through practical co-operation in multilateral fora such as the United Nations, inter alia in the context of the 2024 to 2028 UN Open-ended Working Group on the Prevention of an Arms Race in Outer Space (OEWG on PAROS) in all its aspects, as well as in the framework of EU-NATO co-operation. They will work together to promote norms, rules and principles of responsible behaviour in outer space.

Emerging disruptive technologies

30. The EU and the UK will exchange on security and resilience of emerging disruptive technologies, including the development of international governance efforts on the responsible use of Artificial Intelligence (AI) in security and defence.

Cyber issues

31. The UK and the EU will further develop their co-operation on cyber issues including through the provisions of the TCA and regular exchanges on, inter alia, the cyber threat landscape, respective policy frameworks and practical co-operation in multilateral fora, including the UN.

32. The UK and the EU will also exchange on best practices and advance co-operation to prevent, deter and respond to malicious cyber activities, including through diplomatic measures. The EU and the UK will deepen their exchanges and co-operation on cyber capacity building efforts in support of partner countries.

Countering hybrid threats and resilience of critical infrastructure

33. The UK and the EU will cooperate on research on and analyses of hybrid threats, including by supporting close co-operation between academic institutions and, think tanks, as well as through the European Centre of Excellence for Countering Hybrid Threats.

34. The EU and the UK will hold strategic consultations on their respective approaches and share best practices in developing strategies and policies, including responses to hybrid threats, and explore opportunities for practical co-operation, including cross-participation in exercises.

35. In this context, the UK and the EU will also exchange on their respective approaches and seek to cooperate to enhance the resilience of critical infrastructure in Europe, including underwater infrastructure.

Countering foreign information manipulation and interference (FIMI)

36. The EU and the UK will strengthen their co-operation to counter attempts by malign foreign actors to undermine security and democratic institutions and processes by information manipulation and interference. In this context, the EU and the UK will coordinate approaches and systems to detect, analyse and respond to FIMI in order to raise the costs for malign actors and to strengthen resilience of their respective societies.

37. The UK and the EU will further reinforce information sharing, including on FIMI threat analysis, reporting and best practices, and strengthen co-operation in detecting and responding to FIMI through bilateral exchanges.

38. The EU and the UK will continue close co-operation on collectively responding to FIMI in relevant international platforms and multilateral fora, including the G7.

Counter-terrorism, preventing/countering violent extremism

39. The UK and the EU will develop their co-operation on counter-terrorism and the prevention of violent extremism (based on the provisions of the TCA), including through the EU-UK dialogue on counter-terrorism.

Non-proliferation, disarmament and conventional arms, including small arms and light weapons (SALW)

40. The EU and the UK will work together on the non-proliferation of Weapons of Mass Destruction (WMD) (based on the provisions of the TCA), including through work to strengthen and support global adherence to core international instruments, including the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), the Chemical Weapons Convention (CWC) and the Biological and Toxin Weapons Convention (BTWC), and support for relevant multilateral institutions, including the International Atomic Energy Agency (IAEA) and the Organisation for the Prohibition of Chemical Weapons (OPCW). Co-operation will also cover exchanges on existing and emerging proliferation challenges wherever these occur.

41. The UK and the EU will also work closely together on multilateral conventional and humanitarian arms control, including on SALW.

Capacity building for partners in security and defence

42. The EU and the UK will explore further opportunities for coordination, co-operation and synergies in support of capacity building for partners in the field of security and defence including in the context of EU-NATO co-operation in this field. The European Peace Facility (EPF) enables the possibility for third states to provide voluntary contributions.

Training, education in security and defence

43. The UK and the EU will seek to cooperate in the field of training and education related to peace building, crisis management, security and defence, including through closer co-operation between the European Security and Defence College (ESDC) and the UK security and defence training and education authorities.

44. The EU will seek to allow the UK to increase its participation to the ESDC activities. The UK will seek to adopt the necessary arrangements on its side to facilitate participation of the EU in relevant UK-led training activities. Both, the EU and the UK will increase cross participation in the relevant training and education activities.

45. Furthermore, the UK and the EU will explore opportunities to establish co-operation within the framework of the ESDC Associated Network Partners (ANP), which allows the UK’s institutions to co-organise training and education activities in collaboration with a full member of the ESDC Network.

Situational awareness

46. The EU and the UK will strengthen co-operation through exchanges on situational awareness and threat assessments in areas of common interest, including  classified information. Such exchanges would be carried out in accordance with the Security of Information Agreement.

47. The UK and the EU will explore additional measures to ensure that classified information can be exchanged swiftly, safely and effectively, in accordance with the above mentioned Security of Information Agreement.

Co-operation in third countries and multilateral fora and institutional exchanges

48. EU Delegations and Offices, and UK posts in third countries will seek opportunities to strengthen bilateral co-operation, as well as co-operation within like-minded groups, in areas relevant to the Security and Defence Partnership.

49. The UK and the EU will strengthen co-operation and regular consultations on multilateral affairs, including on matters related to the United Nations, the Organization for Security and Co-operation in Europe and the Council of Europe, and in support of promotion of democracy, the rule of law and human rights in third countries. The EU and the UK will increase regular exchanges on issues of mutual interest in the context of the EU-NATO co-operation framework on the basis of the 3 Joint Declarations of 2016, 2018 and 2023, and in line with the agreed guiding principles of mutual openness and transparency, inclusiveness and reciprocity, in full respect of the decision-making autonomy and procedures of both organisations.

50. The EU and the UK will increase their exchanges on respective contributions and support to UN Peacekeeping Operations.

51. Recognising the importance of forging close and lasting relationships and sharing expertise, the UK and the EU will explore the possibility of seconding staff from and to their respective institutions and collaborating on joint training initiatives.

External aspects of economic security

52. The EU and the UK will explore ways to exchange views on external aspects of their respective economic security policies, in line with ongoing co-operation within the G7, with the aim to address shared risks while maintaining and improving a well-functioning international system based on international law, to continue to benefit from an open economy.

External aspects of the fight against corruption and illicit finance

53. The UK and the EU will strengthen co-operation to tackle illicit finance and corruption in third countries.

Women, Peace and Security

54. The EU and the UK are committed to the full implementation of the Women, Peace and Security agenda, which consists of the United Nations Security Council Resolution 1325 and its follow-up resolutions. To achieve this, the UK and the EU are also dedicated to implementing their respective Women, Peace and Security action plans and strategies to advance the agenda, and will ensure that gender equality is a guiding principle in their areas of co-operation on conflict, security and defence.

55. Therefore, the EU and the UK will exchange good practices, cooperate closely on implementing Women, Peace and Security commitments, and continue close collaboration to ensure gender equality as a political, conflict and security related priority and with an aim to reinforce joint responses to current and emerging security and geopolitical shifts.

External dimension of irregular migration

56. The EU and UK will explore opportunities for co-operation in the external dimension of irregular migration, including addressing challenges such as transnational organised crime, trafficking of human beings and migrant smuggling.

Climate – security nexus

57. The UK and the EU will explore the possibilities of a regular exchange on the climate change and peace, security and defence nexus, exchanging views on policy approaches and promoting joint action, including on data and analytics. The EU and the UK will enhance expert exchanges on issues of mutual interest and share ideas and best practices on how to translate knowledge into concrete actions, tools and instruments.

58. The EU and the UK will enhance exchanges on climate and security in multilateral fora in which they are jointly active.

Global health security

59. The UK and EU will enhance co-operation and information exchange on global health security issues and on preparedness and response to global public-health security emergencies.

Way forward

60. The EU and the UK will ensure monitoring of the implementation of the provisions of this Security and Defence Partnership.

61. The areas identified in the Security and Defence Partnership are to be reviewed regularly in the framework of the Security and Defence Dialogue between the UK and the EU, taking stock of progress made and providing impetus to further strengthen and develop the co-operation.

62. The content of the Security and Defence Partnership is to be reviewed as appropriate.

Adopted in London on 19 May 2025.

1. The territorial scope of the co-operation envisaged by this Security and Defence Partnership will be in line with article 774 of the Trade and Co-operation Agreement. This scope may be modified in future agreements or arrangements. ↩