This article explores the patriation of the Canadian Constitution through the lens of Anglo-Canadian relations. More than a mere legal technicality, the move to transfer the power to amend the Canadian Constitution from the parliament of the United Kingdom to Canada witnessed unexpected debate, as disagreements in Canada collided with British political developments, including devolution, Thatcherism and the end of empire. To fully explore this episode, the article first examines the shared experience of separatist movements in the 1970s. It then turns to analyse the rhetoric surrounding the constitutional crisis. This is followed by an examination of the various episodes in which the constitutional dramas weakened Anglo-Canadian relations, before considering how the Constitution became intertwined with critical political debates in both countries, in particular the politics of devolution and of Thatcherism, testing Margaret Thatcher’s leadership at a difficult time and forcing Pierre Trudeau to reconsider his ‘inclusive’ vision.