British Nationality Act 1981

9 Right to registration by virtue of father's citizenship etc.

(1) A person born in a foreign country within five years after commencement shall be entitled, on an application for his registration as a British citizen made within the period of twelve months from the date of the birth, to be registered as such a citizen if—

(a) the requirements specified in subsection (2) are fulfilled in the case of that person's father ; and

(b) had that person been born before commencement and become a citizen of the United Kingdom and Colonies by virtue of section 5 of the 1948 Act (citizenship by descent) as a result of the registration of his birth at a United Kingdom consulate under paragraph (b) of the proviso to section 5(1) of that Act, he would immediately before commencement have had the right of abode in the United Kingdom by virtue of section 2(1)(b) of the [1971 c. 77.] Immigration Act 1971 as then in force (connection with United Kingdom through parent or grandparent).

(2) The requirements referred to in subsection (1)(a) are that the father of the person to whom the application relates—

(a) immediately before commencement or at his death (whichever was earlier)—

(i) was a citizen of the United Kingdom and Colonies by virtue of section 5 of the 1948 Act (citizenship by descent) or was a person who, under any provision of the British Nationality Acts 1948 to 1965 was deemed for the purposes of the proviso to section 5(1) of the 1948 Act to be a citizen of the United Kingdom and Colonies by descent only ; and

(ii) was married to that person's mother ; and

(iii) was ordinarily resident in a foreign country (no matter which) within the meaning of the 1948 Act; and

(b) either—

(i) became a British citizen at commencement and remained such a citizen throughout the period from commencement to the date of the application or, if he died during that period, throughout the period from commencement to his death ; or

(ii) would have become a British citizen at commencement but for his death.