The same sense of Britain’s lapsed capacity to deliver on the promise of global reach was viewed as a rare opportunity by Scottish and Welsh separatist parties, whose stunning rise to electability between 1961 and 1979 cannot be viewed in isolation from the broader implications of imperial decline. Here, the end of Britain was the avowed political prize, persistently and effectively packaged in the aspirational politics of ‘stopping the world’ so that older nationalities might be retooled for a post-British age. The chapter considers the electoral breakthrough of Plaid Cymru and the Scottish National Party during these years, both of whom won surprise electorial victories respectively at Carmarthen (1966) and Hamilton (1967). Contemporaries were quick to conflate the two events, detecting deeper ruptures in the tumult of Hamilton and Carmarthen. To this day, they mark the onset of ‘devolution’ as a major theme of contemporary British politics, but the connnections to the wider context of global decolonization are poorly understood. This chapter takes seriously the idea that the end of empire was heavily implicated in the rise of separatist political parties in the UK.