This article examines the enduring influence of Charles Dilke's Greater Britain (1868), which persists today in the ambitions of Brexit's proponents. Dilke characterized Britain as the center of a world system bound together by a common identity. Yet his explanation of that identity was riddled with inconsistencies. While he cast it mainly in racial terms, he also proposed cultural and linguistic criteria. These inconsistencies would complicate the efforts to define and delineate the reach of Greater Britain by those who followed in Dilke's footsteps. This includes the leading Brexiteers who have advanced Greater Britain's modern iteration, the Anglosphere, as an alternative to EU membership.