This chapter focuses on challenges to the constitutional integrity of the United Kingdom, from the period of the breakaway of the Irish Free State through to the contemporary campaigns for Scottish independence and for a united Ireland. The centrifugal forces prompted by the Brexit referendum are explored, together with the implications of the COVID-19 pandemic and other contemporary crises. The fundamental complexities of nation-state formations within a multinational kingdom are considered. The fundamental question posed is whether the United Kingdom, as a conceptual, constitutional and cultural unit, can survive the pressures currently being brought to bear on it.