Sovereignty is at the core of the UK's chronically contentious relationship with, and within, the European Union (EU). In order for EU membership to be an expression rather than an erosion of British sovereignty governments must influence the direction of European policy and the level of UK involvement. Labour has, it is argued, established an effective accommodation between continued membership of the European Union and British parliamentary sovereignty understood as the continued efficacy of executive power. Nevertheless, this policy has lacked a wider legitimacy and in key respects Euroscepticism has been reasserted by the Labour leadership. Consequently, when viewed from the perspective of popular sovereignty, the nation and the people, the UK's relationship to the European Union remains highly contested and unresolved. It is this aspect of sovereignty that is central to the Conservative Party's continued Euroscepticism. In the political mainstream, it is argued that Eurosceptic Britishness has become politically dominant however this is complicated by the UK's multi-nationalism and the rise of pro-Europeanism in separatist and regional politics. Alongside this it is proposed that British conceptions of economic sovereignty are in flux following economic crisis, contributing to an overall uncertainty in the UK's European trajectory.