This article examines the flows of migration to and from the United Kingdom in the years immediately after the Second World War. It identifies the paradox that while UK population was in long‐term decline, and the economy suffering from labour shortages, the Labour government chose to encourage emigration to the Dominions, and immigration from Europe, but stoutly resisted immigration from the West Indies. It is argued that the solution is to be found in the contrast between formal definitions of British nationality and informal notions of national identity.