UK Foreign and Security Policy after Brexit

Read Full Report(PDF 201KB)

Despite a looming split, the UK must seek to create a new relationship with the EU while strengthening ties with major European and non-European partners. Such measures could allow the UK to continue to contribute to resolving major security challenges.

This Briefing Paper:

  • Urges government to ensure foreign and security policy is not overlooked as Brexit negotiations over trade and other pressing areas are pursued.
  • Calls for a new post-Brexit ‘special relationship’ with the EU on foreign and security policy, which could be especially important if uncertainty over the approach of the Trump Presidency increases the need for strong European defence cooperation.
  • Argues that the UK’s position as Europe’s strongest military and intelligence power — its ‘security surplus’ — should not be used as a bargaining chip in negotiations.
  • Points out that the UK’s position within the NATO command structure could be affected, with the post of Deputy Supreme Allied Commander (DSACEUR), traditionally held by the UK, possibly being transferred to a European member state that is remaining in the EU.
  • Suggests that the UK may increasingly ‘find itself faced with a European fait accompli on key issues’, and that it will have to work hard to ensure that its interests and views are not an afterthought to the results of US/EU dialogue.

By the middle of 2019 at the latest, it is highly probable that the UK will cease to be a member of the EU. The price of more national control over the instruments of foreign policy that this brings – for example in relation to economic diplomacy – will be a significant decline in influence over the common European foreign policies.

The long -term foreign policy consequences of Brexit may depend, above all, on whether it is followed by an economic revival that can provide the resources the UK will need to support a credible role as an independent international power, while also addressing the deep popular resentments that fuelled the vote on 23 June.

The UK‘s departure from the EU is thus likely to deepen the recent trend towards a security policy focused on national interest. The cumulative effect will be a foreign and security policy that is fundamentally different in emphasis than it was at the height of Blair/Brown internationalism in the decade after 1997.

Trump’s election – on a platform of ‘America First’ – could further encourage this trend, throwing further doubt on whether the post-1945 Western institutional order can now survive. If he seeks to implement the nationalist platform on which he was elected, it may help to bring the UK and the EU closer on defence policy, albeit on a more bilateral basis. It may even lead to a British willingness to discuss defence issues with the EU to a far greater extent than it was prepared to do while it was a member.

Much will also depend on Russia’s response to the dual shocks in the UK and the US. If it were to redouble efforts to re-establish a sphere of influence on its western borders, perhaps as part of a wider bargain with President Trump over the heads of NATO allies, the pressure on the EU and the UK to deepen their defence cooperation would be considerable, potentially diluting any EU instinct to ‘punish’ the UK economically for Brexit.

This paper was updated on 20 January 2017 to correct a minor error on page 5.


Malcolm Chalmers

Deputy Director General

Senior Management

View profile


Explore our related content