jats:pThe Brexit referendum triggered a feverish debate over the future of Britain. Critics warn of a country stripped of its international influence, while advocates insist that it marks the beginning of a new phase in British engagement with the world. This article explores a notable development in the ideological debate. Some prominent Brexit supporters endorse the idea of CANZUK, a union of Canada, Australia, New Zealand, and the United Kingdom. We analyse CANZUK as an attempt to develop a fruitful post-Brexit imaginary and as a case of transnational elite advocacy. We begin by placing CANZUK in the context of debates over the ‘Anglosphere’. We then map the CANZUK advocacy network. Next, we examine past plans for uniting English-speaking polities, tracing the idea back to late 19th-century debates over settler colonialism. We end by sketching some reasons to be sceptical about the project.</jats:p>