This article argues for an essentially political definition of empire with sovereignty at its core, which recognises that British assertions of sovereignty were multiple, mutually contradictory and thus, taken together, incoherent. Tracing the history of conflict between different archetypes of sovereign authority, we argue that imperial crises occurred when empire's different ideas were forced to speak to one another, during world war, for example. The emphasis here on sovereignty and incoherence contrasts with conceptions of the history of the British empire which assert to the contrary that empire was a coherent entity. Such coherence can, we argue, only be maintained by treating empire as a metaphor for broader conceptions of power and thus collapsing the history of empire into other totalising meta-concepts such as global capitalism or Western cultural dominance. Recognition of the incoherence of imperial sovereignty offers new, more nuanced, readings of central concerns in the literature such as imperial violence and the economics of empire.