Theresa May’s gnomic phrase ‘Brexit means Brexit’ echoed around British and international media outlets following the 2016 British referendum to withdraw from the European Union (EU). The ‘British Exit’, or ‘Brexit’, after a process lasting three years and overseen by various Conservative Party leaders, has indeed been achieved.

However, the ongoing Russian invasion of Ukraine has posed a collective threat to the continent, including the United Kingdom (UK). With a renewed effort to cooperate on security matters, the ‘Brexit means Brexit’ aphorism has seemingly become tainted. With political analysts declaring that this renewed closeness is imperative both for saving Ukraine (Blewett-Mundy, 2024) and for the freedom and security of the UK and its EU neighbours (Ricketts, 2024), it is no surprise that there is an interest in analysing the increased momentum in EU-UK security cooperation. In this context, exploring how and why the UK and the EU have resumed their security cooperation is topical.