This article explores conflicting approaches to British citizenship through claims to universalism and difference respectively. It focuses on displaced Chagos islanders in the U.K. to show how an evidently unique case was confronted by the universalizing policies of the U.K. government. First, most displaced Chagos islanders and their second-generation descendants have been awarded U.K. citizenship, but three key limitations - concerning discrimination against 'illegitimacy', one's date of departure from Chagos, and restrictions on the transmission of nationality to subsequent generations - exclude other people who are also considered to be members of the extended Chagossian community. Second, those Chagossians who decide to migrate to the U.K. face significant hurdles in their attempts to establish habitual residence and integrate into the welfare system. The article reveals how Chagossian pleas for preferential treatment - in recognition of their particular history of forced displacement, dispossession and suffering in exile - have been thwarted by the U.K. government's purported commitment to the equal rights of all British citizens.