Co-operation between the European Union and the United Kingdom in Defence, Security, Intelligence and Justice & Home Affairs after BREXIT

Written by Alexander Christiani

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The decision by the British Government to leave the European Union was, in my mind a colossal mistake whose negative reverberations will be felt for many years to come.

However, despite many irritations between the UK and the EU over the years, Britain has decisively contributed to a great number of our common goals, notably the common market, free trade and her leadership in the areas of defence, common security and intelligence. As a permanent member of the UN Security Council, the main ally of the United States in Europe and global leader of European defence and security operations around the world – alongside with the best and most efficient European Intelligence Service – the UK stands out in all these areas. It is one of only two member states possessing “full spectrum” military capabilities-including a nuclear deterrent- and one of only five, spending 2% of GDP on defence.

The European Union would in my mind therefore be well advised to seek further close cooperation with this important neighbour, in order to benefit its own future ambitions.The two relevant strategic documents of the EU are:

  • THE STRATEGIC COMPASS of March 2022.

It is important to point out, that these two EU documents could have never been established, were the UK still a member of the Union.

Since the beginning of the millennium, numerous measures have been taken to improve the EU’s capabilities to cope with complex external and internal security challenges to prepare for a possible common European defence of the EU.

The so called Permanent Structures Cooperation (PESCO) refers to the cooperation between EU member states. It focuses on the strengthening of civil and military crises management, including research and financial instruments. Military and civilian peacekeeping, conflict prevention and  international security missions, are part of a range of tools to deal with current complex security challenges.

For the British Government, on the other side, NATO is the cornerstone of European defence and security.  Greater defence cooperation with the EU has always been viewed as complimentary to NATO and a means of developing the European pillar of that Alliance. Consequently, the UK quite often stood on the brake as far as CSDP is concerned. On the other hand, the Brits have allowed the EU to use its Northwood Operational Headquarters (OHQ), whereby all military or civilian missions of the EU ,as part of its CSDP, are planned and conducted at the military strategic level.

The so-called INTEGRATED REVIEW 2021 on Security, Defence, Development and Foreign Policy describes the vision for the UK’s role in the world over the next decade. It is a comprehensive articulation of the UK’s national security and international policy and sets out a vision for so called GLOBAL BRITAIN. The main objectives are:

  • sustaining strategic advantage through science and technology,
  • shaping the open international order of the future,
  • strengthening security and defence at home and overseas,
  • building resilience at home and overseas.

In this regard, it must be mentioned that general trends in the area of defence and security show a rather gloomy picture which is characterized by a tendency towards an increased hybrid threat.

Political tension between the EU and the UK places the most serious constraints on their efforts to cooperate with each other. This is why the EU and the UK should begin to revitalize their relationships in policy areas that have avoided heated political debate: defence and security. In my mind, the only way for the UK to truly complete BREXIT, is to establish a more institutionalized relationship with the EU. But, at the moment, neither side seems interested in developing this relationship.The UK’s 2021 “INTEGRATED REVIEW on Security, Defence, Development and Foreign Policy“ barely mentions the EU. I would argue that the best way for the UK to preserve its “recaptured sovereignty” in these areas is to accept the existing EU structures and ambitions. At the same time, ad hoc cooperation can also provide a flexible and scalable framework of cooperation with the EU, as envisaged in the so called POLITICAL DECLARATION.

 “GLOBAL BRITAIN” and die “INTEGRATED REVIEW” (IR) envisage productive relationships with Britain’s neighbours in the EU, based on mutual respect for sovereignty  and the UK’s “freedom to do things differently“.

The most important thing is that the IR tents to emphasise relationships with individual European countries rather than the EU institutions or framework as such. In other words, to work with the EU only “where our interests coincide“, such as supporting European stability and security and climate action. The IR notes the EU’s complete absence from the British Defence Command Paper. The UK sees itself as having “uniquely global interests, partnerships and capabilities”. It always singles out that the United States is its most important bilateral relationship.

On the other hand, British participation in the European BATTLE GROUPS showed to an extent the former commitment of the UK to EU as actor in international crisis management .In this regard, however BREXIT resulted in marked gaps in the Battle Group Roster for her next 5-7 years, which other member states could not compensate.


Even though foreign policy and security and defence cooperation remain beyond the scope of current formal agreements between the EU und the UK, there are options to be explored within these limits.

The UK’s historical involvement and important role in shaping the CSDP, as well as its immense security and defence know-how, renders it an invaluable partner to the EU. Likewise, a more capable and well-equipped EU in defence matters, one that is developing a truly strategic partnership with NATO and the US, should – at least in theory – make an attractive partner for the UK. As far as the EU is concerned, third countries, such as the UK, can participate ins CSDP missions and operations through the so called Framework Participation Agreements (FPA) as a third party.

Three possible scenarios for future EU-UK cooperation on foreign, security and defence policy: The first is a legally binding agreement on external security cooperation. This would, however be incompatible with the Johnson’s government approach. The second is no agreement at all, meaning that any future cooperation would be on an entirely ad hoc basis. And the third scenario envisions targeted agreements on specific already existing operations. Furthermore, in the absence of formal or institutional cooperation on foreign, security and defence policy, the EU and the UK are likely to cooperate trough other multilateral frameworks. One thing is quite clear: after BREXIT the UK’s ability to project military power will be largely unaffected and she could exert influence through NATO or other, bilateral arrangements.

The main consequence of BREXIT in defence and security, is the inability of the Union to restore its former competence in executing military missions and operations.

Furthermore, the lack in the British contribution to Battle Groups, the nuclear component ( only NATO),and the loss of a strong advocate of EU matters in the UNSC.

Crime & Justice

In the last decades there has been a noticeable increase in cross- border crime, terrorism and people trafficking. The EU has developed increasingly sophisticated policy measures in response to the change in the threat level, often at the urging of the UK. The UK’s departure from the European Union means decisive changes in the arrangements for cooperation in the field of crime, justice, security and intelligence between the UK and the EU. In the light of the extensive use the UK made of EU crime and justice policies – it was an important UK negotiating objective, to achieve a continuing high level of co-operation after BREXIT. There are many provision in the TCA covering policy and security co-operation, but these provisions are on the basis that the UK is now a third country. It is no longer an EU member state with right to participate in EU law and justice policies or to make use of its agencies and facilities. It has lost its real time access to EU databases in several cases.

It was a strong supporter and contributor to EUROPOL. As a third country, the UK cannot be a member to Europol or be represented on its management board, but the TCA does enable it to continue to co-operate and share information with it. Data exchange would in future be a vital part. The UK will have to ensure that its data standards match those of the EU on an on-going basis.

In the field of crime and justice, the UK government has shown its desire to maintain existing co-operation. This is a broad field where – reversely – the UK would be more interested in the EU than in defence and security matters.

All in all, it is a most complex and still highly controversial affair. There is the TCA, and there seems to be a general – albeit theoretical – desire to work together also in the future. However, the still existing approaches vary significantly. The UK is obsessed by the philosophy of SOVEREIGNTY and GLOBAL BRITAIN, whereas the EU is eager to maintain and protect its status quo, including the ECJ as final arbiter in all controversial bilateral matters. Despite all that, close future co-operation between the Union and Her/or His Majesty’s Government will not only be desirable, but in my view essential to shape a secure and well-founded future for us all.

Written by  

Alexander Christiani, Vice President of the Austro-British Society and former Ambassador of the Republic of Austria to the United Kingdom, is leading the ABS Expert Group.