The governance of the British empire was a staple of constitutional law text books of antiquity. In classic textbooks, a chapter on the ‘Laws of Public Administration’ would sit alongside a chapter on ‘India and the Self-governing Dominions.’ More recent treatment of the legacies of empire have examined the centrality of imperialism in the thought of constitutional scholars that are central to public law teaching today. However, empire rarely, if at all, enters the imagination of contemporary UK public law. The implication is that UK public law is thought to have epistemologically broken from its imperial legacies, initially oriented toward a nation-state centered constitution and then to the transnational constitution that incorporates the UK’s membership of various supranational organisations. This paper counters the ‘break’ from imperialism and begins to sketch out some of the continuities of empire in UK public law, focussing on the war powers prerogative and BOT constitutionalism.