Since British Prime Minister David Cameron stated his intention for the UK to hold an in/out referendum on continued EU membership, there has been much debate regarding the impact of the EU on British policy-making. A potentially fruitful method of assessing this impact is by utilising the conceptual framework of Europeanisation. This paper will illustrate the analytical utility of Europeanisation in this role, and apply it specifically to post-Cold War British security policy-making. This serves the dual purpose of placing a range of documents on important developments in security policy and British involvement in the European integration project into a conceptual framework, whilst also contributing to the wider debate on the causality of the EU on policy-making by Member States.