The British Nationality (Proof of Paternity) Regulations 2006
Section 50(9A) of the British Nationality Act 1981 (as substituted by section 9 of the Nationality, Immigration and Asylum Act 2002) sets out who is a child’s father for the purposes of that Act, as follows: (a) the husband, at the time of the child’s birth, of the woman who gives birth to the child, or (b) a person who is treated as the father of the child under section 28 of the Human Fertilisation and Embryology Act 1990, or (c) where neither of those paragraphs applies, any person who satisfies prescribed requirements as to proof of paternity.