similar to Commonwealth citizens and are not considered aliens. The Ireland Act also reestablished British citizenship for Irish citizens who were domiciled outside of the Republic when the British Nationality Act 1948 came into effect. Because that Act contained provisions that dealt with "a person who was a British subject and citizen of Éire on 31 December 1948", the conditions laid out in British law determining who became Citizens of the United Kingdom and Colonies (CUKCs) were dependent on who were Irish citizens under Irish nationality law. When the Irish Free State was established on 6 December 1922, it consisted of the whole of Ireland. Northern Ireland opted out of the Free State on the next day. However, all individuals domiciled on the entire island on 6 December are considered Irish citizens. Consequently, when the BNA 1948 became effective, Irish citizens living in Northern Ireland automatically lost British citizenship, although this was not intended by Parliament. The Ireland Act restored British citizenship to any individual domiciled in Northern Ireland on 6 December 1949 who otherwise would have had the status if not for Irish law. The Ireland Act additionally conferred CUKC status on Irish-born persons who did not receive Irish citizenship at any point prior to 18 April 1949. Individuals who left Ireland before 1922 and who were not resident in 1935 may be eligible for registration as Irish citizens while also being able to claim British citizenship. A claim to British citizenship may be established by: birth to the first generation emigrant, consular registration of later generation births by married British citizen fathers within one year of birth prior to 1983, registration of birth to unwed British citizen fathers, or registration of birth to mothers who were considered British citizens between 1949 and 1983. In some cases, British citizenship may be available to these descendants in the Irish diaspora even when Irish citizenship registration is not, as in instances of failure of past generations to timely register in a local Irish consulate's Foreign Births Register before the Irish Nationality and Citizenship Act 1986 and before births of later generations. Prior to 1983, anyone born in the United Kingdom other than children of diplomats were automatically British citizens at birth. After the British Nationality Act 1981 took effect, children are only citizens at birth if at least one parent is also a British citizen or considered "settled" in the UK.