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British Nationality and Status of Aliens Act 1914
This legislation came into force on 1 January 1915 as 4&5 Geo. c.17. British subject status was acquired as follows:
birth within His Majesty's dominions
naturalisation in the United Kingdom or a part of His Majesty's dominions which had adopted Imperial naturalisation criteria
descent through the legitimate male line (child born outside His Majesty's dominions to a British subject father). This was limited to one generation although further legislation in 1922 allowed subsequent generations born overseas to be registered as British subjects within one year of birth.
foreign women who married British subject men
former British subjects who had lost British subject status on marriage or through a parent's loss of status could resume it in specific circumstances (e.g. if a woman became widowed, or children immediately upon turning 21).
British subject status was normally lost by:
naturalisation in a foreign state, such as the United States of America or France
in the case of a woman, upon marriage to a foreign man. Prior to 1933, British subject status was lost even if the woman did not acquire her husband's nationality.
a child of a father who lost British subject status, provided the child also had the father's new nationality.