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Updated: May 29, 2021

Author: Santhiya V, III year of BBA.,LL.B(Hons) from Alliance University.


From February 1, 2020, the United Kingdom is officially not a part of the European Union. This withdrawal of the United Kingdom from the European Union is known as Brexit. This research paper will look into the future of the security and defence policy post Brexit. This research paper will also look into the relationship between the EU and the UK in security and defence policies before Brexit, and it will also look into the degree to which the UK was integrated into the EU’s decision making and implementation process. This research paper will also analyse the claims made by the government regarding the UK defence and security post Brexit. Finally, this research paper will also look into how these changes made post Brexit have affected the security and defence policies of the EU.

Key Words: - Brexit, European Union, United Kingdom, Security and Defence.


The EU is a regional organisation created for the development of the countries on the European continent. The Treaty of European Union is one of the important treaties of the European Union. Article 49 of the Treaty talks about the application to join the EU. On the other hand, Article 50 of the Treaty talks about the withdrawal of the same. Till now, the UK is the only country to have ever invoked this provision of the Treaty of the European Union.

On March 2017, the UK officially gave their two-year notice to the EU by invoking Article 50 of the Treaty of the European Union and finally left the EU of January, 2020. During this period of two years, the UK and the EU had to discuss the withdrawal agreement and the relationship between the EU and the UK post Brexit.

One of the main sectors that is to be affected in the EU because of the Brexit is the security and defence sector. This is mainly because the UK is one of the countries of the EU to have a strong-armed forces and other materials that are required for military operations.

This research paper will look into that. It will look into how the security and defence of the EU was, before, during and after Brexit.


In the EU, France and the UK are the two most important countries in regard to the defence and security role. The UK played a major role by contributing to the security of the EU through intelligence collection and analysis in support of both law enforcement, especially counter-terrorism operations, and the full spectrum of military operations. The UK’s armed forces have a considerable reach and it has existing relationships beyond Europe.

Unlike other countries on the European Continent, the UK has particular strengths in the high-end war-fighting spectrum, but also in their ability to provide scarce enablers to international operations, and in the field of defence capacity building. It can be seen that the UK had a huge impact on the security and defence of the EU. So, what issues did the EU have to face post Brexit?


Whether the Brexit has made a huge impact on the security and defence of the EU, that it cannot reach its original position back?


Yes, Brexit did have a huge impact on the security and the defence of the EU.


  • To analyse the original position of the EU in security and defence;

  • To look into how Brexit affected the security and defence of the EU;

  • To study the difference made by the Brexit in the security and defence of the EU; and

  • To look into if the EU can overcome this change.


The present research paper uses the most recent available published secondary data. To achieve the objectives, the secondary data was used. The secondary data are mainly used from government departments for policy information,

• Judgments/Acts

• Research reports, books and articles,

• Newspaper’s clippings,

• Online sources,

• SCC journals and bare acts.


The UK has been ranked among the world’s most capable and influential nations in defence and security. Its defence capabilities extend to a wide range of conflicts, crises and operations both in their home country and in other countries. Post World War II, Britain continued to spend a large part of GDP on its defence. Despite the fact that this figure has dropped by approximately 1% in every decade since the 1960, the UK still ranks as one of the tops five countries for defence budget, globally.

In the years prior to 2015 Strategy Defence and Security Review (SDSR), because of the 2019 financial crisis, the financial austerity, which refers to a set of economic policies that government implements in order to control public sector debt, shaped the defence and security decision making, rather strategic analysis. The 2010 SDSR was mainly focused on fiscal realities and the Treasury’s focus on rebalancing the defence budget, which resulted in a reduction of 8% in the defence spending, which further resulted in an approximately 20% reduction in the UK's conventional military combat capabilities.

The next SDSR, held in 2015, focused on a substantial shift in the national and global context. In total, £178 billion was set aside for the spending on equipment and equipment support over the next decade.

The UK has shown interest in developing bilateral defence relationships with other European countries, outside the EU, especially it has heavily invested in its relationship with France in the recent years. A new Anglo-French relationship, which was rooted in collaboration on nuclear weapons technology and the increased interoperability of armed forces, was created on the 2010 Lancaster House treaties.

This treaty was formed on the closer relationship between the UK and France to make way for a greater burden-sharing in the EU and NATO. France has preserved the idea of Anglo-French coordination at the heart of a successful EU foreign, security and defence policy despite the restraint behaviour of recent British governments in respect of an EU defence policy. The UK’s commitment to the EU is to support the EU Battleground concept by providing troops and equipment. The defence and security of the UK also includes, Counterterrorism, Combating serious and organised crime and Cybersecurity.

The United Kingdom has advocated for closer bilateral and multilateral operations with European partners within mutually agreed-upon frameworks that exist outside of the formal structures of the EU or NATO, but are firmly within a common legal and policy framework. This has proven useful in safeguarding sensitive information needed to support operational intelligence work. However, in the field of analysis, the UK backs the work of relevant EU and NATO multilateral units. The UK can also draw on its Five Eyes intelligence alliance, which includes Australia, Canada, New Zealand, and the United States.


Earlier, the EU’s arrangement for the collective foreign and security policy was Common Foreign and Security Policy (CFSP) and Common Security and Defence Policy (CSDP), these were conducted on an intergovernmental basis.

The purpose of CFSP is to coordinate the foreign policies. The EU’s aims for a defence policy are given in the Treaty on European Union, which was very vague until the 1998 Anglo-French summit in St Malo, where it was agreed to push for greater EU defence by the UK and France. As these two were the two most prominent military power in the EU, the UK-French agreement laid the basis for the EU’s CSDP. The purpose of CSDP is much different than providing the defence for NATO. It focuses on preventing, managing and resolving conflict using both military and civilian resources. This includes providing peace-keeping forces, providing security for elections to take place in states in conflict, training police, armed forces and security personnel in third countries, and monitoring disputed borders, ceasefires and peace agreements.

The different roles that are undertaken by the EU and its member states are collectively known as ‘Petersberg tasks’. The CSDP also aims to enhance the collective capabilities of the armed forces of the member states by coordinating the military procurement and enhancing interoperability by developing joint military forces, which are capable of undertaking Petersberg missions.


The most important contribution made by the UK to the EU security is the collection of intelligence and analysis in law enforcement, mainly counterterrorism operations and the full spectrum of military operations. The UK has pioneered in sharing of counterterrorism-related intelligence among other European countries, allowing for real-time investigation and disruption of terrorist operations all across European. It has also helped its partner states by deploying their own resources on a bilateral basis.

Furthermore, the UK has provided advice and assistance in improving other related investigative and law-enforcement processes. In the military sector, the UK has been a pioneer in the collection, analysis, and usage of intelligence in the development of defensive measures for use in conventional and unconventional warfare. As all forms of warfare become more reliant on a rich intelligence picture, the power to generate strategic and tactical intelligence and integrating it into combat operations is becoming increasingly important.

The UK has led the way in integrating intelligence from military and civilian agencies into military campaigns, as well as in effective defensive measures against hybrid-warfare techniques which ranges from cyber to subversion. The UK's armed forces assist in the collection of intelligence on a tactical and strategic level through the use of dedicated platforms. For example, the UK has more than half of all combat intelligence, surveillance, and reconnaissance heavy unmanned aerial vehicles and roughly 40% of all electronic-intelligence aircraft among the EU's 28 member states.


Out of all the member states of the EU, the UK has the largest defence budget and alone accounts for nearly 25% of the spending for the defence equipment-procurement among the member states. Along with France, it is one among the two largest spenders in Research and Development. It is worth noting that the UK and France are also in a league of their own when it comes to defence investment spending – procurement and Research and Development – in terms of absolute spending levels as well as the average percentage of defence spending that goes towards these categories each year.

The UK has an interdepartmental budget line for the Conflict, Stability, and Security Fund, on which any department or agency on the National Security Council can bid. In 2016, this fund had just over £600 million. Some of this funding has been used to provide the EU’s CSDP with conflict advisors, which is an attempt to strengthen the ability of these missions to address the root causes of conflict. Around 13% of British Official Development Assistance (ODA) spending is allocated to governance and civil-society projects, which, among other things, are intended to serve conflict-prevention purposes.


The British armed forces remain among Europe’s most capable fighting forces. They also have distinct advantages in high-end fighting war spectrum, but also in their ability to provide enablers to international operations, and in the field of defence capacity building. They also have considerable reach and existing relationships beyond Europe, like the Gulf region, Nigeria and Pakistan. In the land domain, along with its NATO Allied Rapid Reaction Corps Headquarters, the UK provides a high quality standing deployable corps headquarters, which could either serve as a land tactical headquarters or as a combined joint-task-force headquarters for a land heavy joint operation.

In the air domain, the UK holds nearly half of all the heavy transport aircraft and more than a quarter of all the heavy means of transport helicopters among the 28 member states of the EU. The Royal Navy holds half of the nuclear-powered attack submarines in the EU, followed by France, which also provides a similar capability.

The UK boats have a special operations-forces deployment capability and land attack cruise missiles. Though expensive, the UK’s aircraft-carrier programme will restore a carrier strike capability, and it could be used to generate European naval task groups. The UK can provide air defence and nascent ballistic-missile defence capability by using its Type-45 destroyers. The Royal Marines are probably Europe's most capable amphibious landing force, capable of deploying a brigade-sized force depending on shipping and support-asset availability.

The UK's afloat-support vessels also demonstrate the country's capacity to deploy outside Europe's borders.


Originally, it was intended that new arrangements would come into force for the EU-UK foreign, security and defence policy cooperation before the end of the transaction period. The Political Declaration, which outlined the aims for the post-Brexit EU-UK relationship, included detailed proposals on the terms of the future relationship in the fields of foreign, security and defence policy.

This Declaration specified cooperation in areas such as sanctions, the defence industry and research, and consular cooperation in third countries. It also talked about the chances of the UK being invited to the EU foreign minister meetings and raised the likelihood of the UK participating in EU military operations. Given that the Political Declaration was a jointly agreed-upon document, it has come as a surprise to the EU that the UK has refused to negotiate future foreign, security, and defence policy cooperation and the UK also did not mention about the cooperation in the foreign, security, and defence sector, when it published its own draft texts for the future EU–UK agreements in May 2020.

The UK has decided to negotiate exclusively on the future trading relationship with the EU, but not about the other non-trade and border-related issues.

Since Brexit in January 2020, the UK has been operating as per the terms of the Withdrawal Agreement, which also included provisions to cover the UK’s relationship with the EU’s security and defence policy during the transition period.

This would mean that the UK has committed to follow the EU foreign policy and security positions without taking part in the institutions that determine these policies, which includes the Foreign Affairs Council, the EU Military Committee, the Political and Security Committee, and the attendant committees and working groups that define and implement the EU’s foreign, security and defence policy. As a result, the UK is formally committed to playing this shadow role in the EU's foreign, security, and defence policy until the end of 2020 while remaining absent from decision-making and following EU positions but having no substantive role in their implementation.


In a comparatively short period of time, the EU–UK relationship in foreign, security, and defence policy has been changed. The UK has moved from its position as a prominent member state, which was important to the decision making and implementation process, to shadowing the EU foreign and security policy for a brief period of time, during the transaction and, finally, to the current state of ambiguity regarding how this relationship will evolve.

As on December 2020, the EU-UK relationship on foreign, security and defence policy seems to move from the arrangements established for the transition period to a situation where there are no formally established rules for cooperation.

But this does not mean that there is a lack of a foreign, security and defence policy relationship between the UK and the member states of the EU. The European bilateral, mini-lateral and multilateral relationships will all resume, but the unsettled EU–UK relationship will restrict the scope of future cooperation. There are three alternative scenarios regarding the future foreign, security and defence relationship between the UK and the EU that could be predicted. They are: integrated player, associated partner, detached observer.


The EU follows a foreign policy decision-making system in which it keeps the non-member states outside the mechanisms of decision-making. By leaving the EU, the UK will no longer be a participant in the Foreign Affairs Council, the European Council, Political and Security Committee, its working groups and the secure COREU communications network. But the UK could still participate by using a special status. For example, in the EU's foreign and security policy-making infrastructure, the UK could take part in it by an EU+1 arrangement. This would pave way for the participation in the Foreign Affairs Council for relevant agenda items and Political and Security Committee (PSC) and its working group. The UK’s foreign policy would remain mostly in correspondence with the EU’s portfolio of foreign security and defence policy.

Regarding the CSDP, the UK might remain outside the EU but inside the CSDP. The UK would continue with its commitments to the current CSDP military and civilian operations and participate in the future missions also, and it would also continue with its commitment to provide the EU with a Battlegroup and to remain on the roster of Battlegroups available for deployment.

The UK can also have associate membership status of the European Defence Agency (EDA) and participate in projects in a case-by-case basis and be granted the observer status in the Agency's Steering Board and make a contribution to the EDA budget. In this arrangement, the UK’s diplomatic capacity and military capabilities would be added in the EU's foreign and security policy for mutual benefit.


The relationship between the EU and the UK could also replicate the relationship between the EU and Norway, which means that the UK would align itself with the EU foreign policy declarations and action, like the sanctions, under the invitation of the EU. Exchanges on foreign policy issues would be on a ‘dialogue’ basis, rather than allowing for direct participation.

In case of military planning, the UK would remain outside the EU’s structure but might decide to participate in the implementation aspects. This could include the signing of a Framework Participation Agreement (FPA) to allow for case-by-case participation in CSDP operations. The UK could also choose to sign an administrative arrangement with the European Defence Agency (EDA) allowing it to participate in EDA projects, but it would lose control of the Agency's strategy. The UK may also wish to discuss continuing its permanent presence in an EU Battlegroup, as Norway is doing now. Under this scenario, the UK would give up its ability to have direct control over the development of EU foreign, security, and defence policy, but would continue to engage in EU activity as an adjunct to a preference for a largely UK-centric perspective.


Under this, the UK would remain politically and organisationally separate from the EU’s foreign and security policies. This does not mean to say that the UK’s foreign policy might be at odds with the member states of the EU, but rather it has decided to maintain an officially disconnected stance with regard to EU foreign and security policies. The UK might prefer for continue the present bilateral relationship with the members of the EU and use this as a way to influence the EU foreign and security policy, rather than influencing through a third party.

This would provide a great degree of autonomy for the UK, but a low level of influence on the EU’s foreign and security policy. On CSDP, the UK may follow the practice of the US, who has not participated in the EU's military CSDP missions but has participated in civilian CSDP missions on a case-by-case basis. The UK may also decide to use this in working in separate missions, rathe rather than the the EU’s military deployments.


The UK chose to exit from the EU on March 2017 and finally left the EU in January 2020. The negotiations regarding this also took place during this period of time. They had more than two years for this negotiation. But they did not have a proper discussion regarding the foreign, security and defence of the EU, in which the UK played a vital role. The importance of the UK in the EU’s defence and security is explained above. There is no agreement between the EU and the UK regarding the foreign, security and defence policy.

Failing to reach an agreement regarding these would let to issues between them. The only solution regarding this is that there should be an agreement between the EU and the UK as soon as possible, resolving the same.

Now, to look into if the Brexit has made a huge impact on the security and defence of the EU, that the EU cannot come back to its original position. The UK has surely made a lot of contributions to the EU in the security and defence and Brexit would also have a huge impact on it. And it is also true that they cannot come back to its original position, considering all the contributions it had made. But it can be back on its own feet with a little bit of more help from the other members of the EU.


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