Both the desire and the inability to “keep them [immigrants] out” grew out of one of the central contradictions of imperialism. Part of the ideological justifi cation for empire was the insistence that colonization would produce substantial benefi ts for colonial subjects, including the unrestricted ability to enter and live in the United Kingdom. Found in both imperial tradition and law, this right to move freely across national boundaries could also be exercised by citizens of former colonies that had joined the Commonwealth after achieving independence. But imperialist ideology also assumed that Britons were racially and culturally superior to their non-white subjects in foreign lands, and a range of negative attitudes about Asians, Africans, and West Indians (collectively described as “coloured”) pervaded British society. Consequently, when large numbers of immigrants from the colonies and “new” Commonwealth (e.g., India and Pakistan) began to arrive in England after the Second World War, they were viewed with suspicion.