Registration is the only way in which children can become British and is also used for adults in special circumstances. It is necessary for those over ten years old to be of good character, but it is not necessary to demonstrate knowledge of the language or of life in the UK. One example of the use of registration is to address problems created by discrimination in the past. For example it is now possible for people born to certain British mothers between 7 February 1961 and 1 January 1983 to register as British. At the time when they were born, only British fathers could pass on their nationality to children born abroad. This discrimination was removed in 1983, but the effects of the historic different treatment remained, as indeed they still remain for people born abroad to British mothers before 7 February 1961.

Some changes to the categories of people eligible for registration, notably the children of serving members of the Armed Forces, children born outside the UK to British citizens “by descent”, British Nationals (Overseas) who have no other citizenship or nationality and the children of British mothers, whenever they were born, were included in the Borders, Citizenship and Immigration Act 2009. These changes took effect on 13 January 2010.