Four options for EU-UK defence cooperation post-Brexit


Phase two of the Brexit negotiations is starting and all eyes are on the future economic partnership. The other key issue – the future security partnership – is often neglected. One reason for this neglect is that stakes are lower in this policy area that is far less integrated in the context of the EU. A second reason is that there seems to be more room for compromise. In fact, both Brussels and London have indicated that while basing post-Brexit defence cooperation on existing models, they might strive for a more ambitious version. What does this mean in practice? This blog post assesses two existing and two new models for defence cooperation in light of EU and UK interests. 


In her speech in Florence on the future of EU-UK relations in September 2017, British Prime Minister Theresa May advocated a “deep and special economic and security partnership.” She underlined that the UK was “unconditionally committed to maintaining Europe’s security”. This message also clearly stood out in the British government’s paper on the future partnership in foreign policy, defence and development. The paper called for a unique security partnership that, while mirroring aspects of existing EU-third country cooperation, should go beyond it.

In a subsequent speech, the EU’s chief Brexit negotiator Michel Barnier emphasised that security, defence and foreign policy should be key components of an ambitious future relationship. The UK is a key player in these fields: it is a nuclear power, a leading NATO member, and a permanent member of the UN Security Council. A document published by the EU’s Article 50 Task Force in January 2018 stated that existing cooperation frameworks with third countries should be taken into account and mentions three options: ad hoc agreements, a Framework Participation Agreement (FPA), or a new and more ambitious framework applicable to third countries.

Following this line of argumentation, this blog post presents two prominent existing models (Norway and Switzerland) and two more ambitious frameworks (‘defence associate’ and ‘Norway Plus’). The models are assessed in light of EU and UK interests. This blog post deepens and updates an earlier analysis on the topic.

1 Switzerland: flexible and selective

EU-Swiss security and defence cooperation is flexible, selective and mostly civilian. It is based on informal political consultation at all levels. As a neutral country, Switzerland is not part of the EU’s Battlegroup (BG) scheme. It has contributed to eight EU crisis management missions and operations based on ad hoc participation agreements. The focus was on civilian missions. Since 2012, Switzerland participates in defence projects and programmes of the European Defence Agency (EDA) based on an Administrative Agreement.

For the UK the Swiss model could have some advantages. It has signalled interest in “collaboration in European Defence Agency projects and initiatives”. In the past, the British contribution to the Common Security and Defence Policy (CSDP) was already skewed towards civilian missions. As a Clingendael report shows, it contributed more than 4% of the civilian personnel to the CSDP while its share of military personnel (less than 1%) was lower than that of Turkey. A civilian focus would allow the UK to remain engaged in EU crisis management without subjecting its troops to the EU’s military chain of command.

However, the Swiss model would not be mutually beneficial. The UK would not participate in military operations that are in its declared interest (and not in that of the US/NATO). The EU in turn would not profit from the UK’s military expertise and strength. In addition, the Swiss themselves are interested in closer relations including a more formal FPA for civilian missions and access to the research component of the European Defence Fund (EDF).

2 Norway: a closely integrated outsider

Norway is a key NATO member and a closely integrated outsider in EU security and defence policy. Formal coordination is restricted to biannual consultations in the margins of the European Economic Area Council meetings. In addition, there are bilateral contacts at all levels and informal consultations on issues of common concern with the European External Action Service and Council working groups. Norway has an Administrative Agreement with the EDA since 2006 and participates in the Nordic Battlegroup since 2008. It joined more than ten CSDP missions and operations on the basis of a FPA, even if its personnel contribution was consistently smaller than that of Switzerland. Norway is the only third country that participates in the EU’s Preparatory Action on Defence Research (€90 mln for 2017-9) to which it contributed €585.000 for 2017.

The Norwegian model comes closest to the deep and special partnership that the UK is seeking. However, the key issue is that Norway’s influence on EU decision-making is limited. Contributions of third countries to CSDP operations are generally “without prejudice to the decision-making autonomy of the EU”. Opportunities for more informal decision-shaping are also restricted. Third country contributors are brought in late in the planning process and are only granted full access to EU-issued documents once their participation has been approved by the Political and Security Committee (PSC). Norway has been calling for full participation in the decision-shaping process for almost two decades. It keeps a close eye on recent developments such as the activation of Permanent Structured Cooperation (PESCO) and is interested in access to the research and capability windows of the EDF.

3 Defence associate: membership minus veto

The outlined limitations and the fact that British defence and security capabilities are vastly superior to those of Norway or Switzerland probably mean that we ought think beyond existing models. A look into the membership categories of the Western European Union (WEU), the precursor of today’s CSDP, provides some inspiration. European NATO members could apply for an associate status, which would allow them to participate in formal decision-making processes without having a veto right. Associate members could join WEU military operations and would contribute to the budget of the Council. Non-NATO EU members that weren’t part of the WEU such as Denmark were eligible for an observer status. They were allowed to attend and speak at meetings of the WEU Council but could be required to leave the room by majority vote.

In theory, the UK could be granted the status of ‘defence associate’ allowing it to participate and speak in PSC or even Foreign Affairs Council meetings without voting rights. It could be granted a similar status in the PESCO Council as well as the EDA Steering Board. In return for a substantial financial contribution, it could participate in the defence research and capability windows of the EDF. Its participation in CSDP missions would remain largely unchanged. The UK could continue to sit at the table, could influence EU decision-making processes, and would have maximal flexibility in terms of its contribution. Considering the UK’s potential military and diplomatic contribution as well as the broad range of shared threats and challenges, such a deep and special partnership could also be beneficial to the EU.

However, such a ‘membership minus’ model faces important legal and political hurdles. The EU Treaties do not foresee an associate or observer status. More importantly, it would contravene two of the EU’s core principles: safeguarding decision-making autonomy and preventing that a third country has the same benefits as a member state. In January 2018, the Article 50 Task Force was quite clear on the derived red lines:

  • No participation in Council or PSC meetings
  • No lead on Battlegroups or CSDP operations
  • No provision of EU Operation Headquarters (Northwood in the British case)
  • Participation in PESCO projects by invitation only, subject to general criteria for third countries and to approval by the Council in PESCO format
  • No participation in management and ad hoc activities of EDA
  • No benefits from the EDF equivalent to those of member states

The Task Force added another political consideration, namely that a new EU-UK partnership should “not disrupt the EU’s relationships with [other] third countries”. These conditions set clear limits on the depth and specialness of the future EU-UK defence partnership.

4 Norway +: performance-based differentiation   

Considering these red lines, what could the more ambitious framework the Article 50 Task Force mentioned look like? A new framework for EU-third country cooperation could follow a performance-based logic. The underlying idea would be that a third country is granted access to informal decision-shaping as long as it subscribes to EU values and commits to making a substantial contribution to the EU’s security and defence policy. This logic would generally be in line with Barnier’s statement that any voluntary UK participation should “confer rights and obligations in proportion to the level of this participation”. The exact balance could be spelt out on a case-by-case basis in enhanced partnership agreements as suggested in the aforementioned Clingendael report.

A performance-based logic raises two central key questions. First, what is meant by access to informal decision-shaping? In this regard, the EU could learn from NATO’s more differentiated partnership menu. The most elaborate options are tailor-made enhanced opportunities partnerships offered to the most interoperable partners including EU members Sweden and Finland. The EU could hold regular political consultations with its enhanced partners at ministerial and strategic level. They could be invited more frequently to the PSC to discuss issues of common concern including developments regarding PESCO, the EDA and the EDF. The EU could also ensure that a substantial operational contribution would entail earlier involvement in the planning process for EU missions and operations.

This leads us to the second question: What does “substantial contribution” mean? The PESCO notification for instance states that third countries can participate in projects upon invitation if they “provide substantial added value …, contribute to strengthening PESCO and the CSDP and meet more demanding commitments.” These criteria and commitments still have to be developed. Generally speaking, and going beyond PESCO, criteria could be either qualitative (e.g. participation in the Battlegroup scheme) or quantitative (e.g. fixed financial contributions). In terms of the UK’s input, the EU is interested in intelligence exchange, expertise in capability development as well as strategic assets and personnel for CSDP operations and missions. The exact content of this substantial contribution would be subject to negotiation.

A Norway Plus model would be of mutual interest. It would generally be open to other third countries such as Norway itself that is seeking closer cooperation with the EU. Upgrading existing arrangements along a performance-based logic could represent an incentive for the UK as well as other third countries to make a more substantial contribution than today to the evolving European Security and Defence Union.


The table below provides an overview of the four models presented in this analysis. These do not preclude sui generis versions depending on the characteristics and preferences of third countries. Models will also have to evolve in light of ongoing developments in EU security and defence cooperation. For the UK this dynamic process has already started. The most immediate question is what happens during the transition period (presumably 2019-2020). According the European Council, the whole of the EU acquis should continue to apply while depriving the UK from decision-making powers. For CSDP this would mean that the UK no longer participates in Council decision-making, but remains bound by its decisions and related financial commitments (e.g. EDA budget). A specific consultation mechanism is to be established to ensure information exchange. Yet, the negotiation guidelines on transition foresee the option concluding an EU-UK agreement in the area of CFSP and CSDP during the transition period. The acquis’ specific CFSP provisions would then cease to apply to the UK upon the agreement’s entry into force.

Summary: Four Models for EU-UK defence cooperation post-Brexit




Political coordina-tion EDA CSDP BGs EDF PESCO


Ad hoc political consultation at all levels Admin. Agreement Ad hoc based on Participation Agreements / / /


Formal political dialogue + informal consultations Admin. Agreement Participation in civilian and military missions based on FPA yes Potential participation and contribution to research window Invited Third State participant
Norway +


Formal dialogue PLUS enhanced access to informal decision-shaping Enhanced partner Regular invitations based on Enhanced Partnership Agreement yes Participation and contribution to research window


PESCO partner (regular invitations, engaged at project level)
Defence Associate Observer status in formal decision-making Associate Continuity based on Deep and Special Partnership Agreement yes Participation and contribution to both windows (special associate status) PESCO associate  (engaged at project and ministerial level)

Source: Nicole Koenig (2018)

Although the UK’s unconditional commitment to European security was an important signal, there is still a risk that difficult trade negotiations could have a negative impact on those on security. In addition, there are areas where security and the Single Market meet, notably the EDF. Overall, one thing should be clear: in an interconnected world European and EU security remains inseparable. As Barnier said, “there must be no horse-trading over the security of Europeans”. A mutual commitment to pragmatic and constructive negotiations in this domain is thus of the essence. The Munich Security Conference in February 2018 would be a good occasion to visibly renew this political commitment.