This is a chapter for the Europe Today textbook. The UK once prized itself on its relative stability following the Second World War - as France transitioned from the third, then the fourth, then the fifth republic, Germany was getting to grips with a new role in the world, and Italy cycled through Prime Ministers (ten changes between 1946 and 1960), the UK saw itself as a beacon of stability even as its empire was disbanded. Today, however, the picture is different. British politics is undergoing a realignment, accelerated by Brexit but echoing changes seen in other advanced Western democracies. The foundations of the UK seem to be under increased threat, with separatists from within Scotland and Northern Ireland on the ascendency, and even for some within Wales and, indeed, England. This chapter explores these changes.