This book explains the immigration and citizenship policies in Britain that repeatedly postponed the creation of British citizenship until 1981. It examines the alternative citizenships of British subjecthood and Commonwealth citizenship, and demonstrates how the complex rules of citizenship and immigration were devised in response to the need to build and transform those 'global institutions', the British empire and later the Commonwealth. In covering these areas, this work extends the research beyond this century. It argues that Britain's formal membership has always been attached to the global institution and that the creation of British citizenship was rejected as long as policy-makers in Britain considered it beneficial to maintain the global institution in some form. In addition to the division between the holders and non-holders of British subjecthood, there was a future division among British subjects: those in Britain and the Dominions were regarded as kith and kin, whereas those in the colonies only had the same nominal status. The affinity between those in Britain and the Dominions was institutionalised in 1914 by the common code system, whereby Dominion governments were to adopt identical citizenship legislation. Post-Second World War immigration policy was, in practice, a continuation of pre-war policy, with an all-embracing citizenship law alongside exclusive immigration controls. The enactment of the British Nationality Act 1981 was a belated acknowledgement by the British government that its long-standing efforts to maintain the citizenship structure that enabled the alternative and national types of citizenship to co-exist had been abandoned by the Immigration Act 1971.