This chapter assesses British party policy (as expressed in general and European election manifestos) and public opinion (using Eurobarometer data) towards foreign and defence policy cooperation within the EC/EU. The chapter first analyses party positions towards and public support for these matters. It then assesses party and public views towards the EU’s role vis-à-vis NATO, specific proposals related to the EU’s foreign and defence policy role that were debated in the 2000s and attitudes towards the idea of a European army. The chapter argues that the Conservative, Labour and Liberal parties consistently supported the principle of foreign policy cooperation on an intergovernmental basis within the EU. However, defence policy cooperation and specific developments related to the EU’s foreign policy role proved more controversial. British public opinion regarding cooperation in these areas was confused. Despite the political class being more comfortable with cooperation on foreign policy matters, there was greater public support for the EU possessing a common defence policy. Public and political opinion were largely in accordance regarding specific issues posed by the EU’s foreign and defence policy roles. Meanwhile, the British public rejected the idea of a European army—but did appear to back a limited European defence capability.