Citizenship revocation is often presented in a national-security context as a practice reserved for the most dangerous and undesirable of citizens – one to be used against terrorists. And yet, as the ethnicity or religion of the citizen becomes a focal point in the everyday reporting of cases, present-day revocation is also entangled in the politics of Britishness and belonging. This paper shifts the focus away from the terror-security narrative by examining another point in Britain’s history when citizens were stripped of their citizenship rights. It explores archival material related to the Commonwealth Immigrants Acts of 1962 and 1968 when citizens who held Citizenship of the United Kingdom and Colonies were divided. As the distinctions between legal categories of citizen and immigrant broke down, a new category was created, and the government began to legislate for the ‘non-belonger’. Drawing on this analysis, I argue that through the practice of citizenship revocation today, the older imperial practices underpinning British citizenship are rendered visible.