Post-Brexit EU/UK security cooperation: NATO, CSDP+, or ‘French connection’?

The purpose of this article is to understand the EU/UK security relationship after Brexit and the institutional form(s) it may take. Taking stock of the literature on the consequences of Brexit for European foreign affairs, this article employs a question-driven approach to examine uncertainties regarding the future EU/UK security relationship. These questions relate in particular to the United Kingdom’s commitment to European security after Brexit, the nature of post-Brexit developments within the Union, and the European Union’s willingness to afford the United Kingdom a substantial role after withdrawal. This article examines each of these questions in turn, before considering the viability of three frequently mooted institutional arrangements post-Brexit: UK participation in the CSDP as a third country; increased engagement with NATO that becomes the main platform for cooperation between the United Kingdom and the European Union; and the enhancement of bilateral ties between the United Kingdom and key European allies – especially France.