United Kingdom - Passport & Nationality - British Citizenship by Double Descent (12(5)1948)
If you have a paternal grandfather born in the UK, there are circumstances where his British nationality could pass down two generations (i.e. by Double Descent). Normally, British nationality can only pass down one generation from a UK-born grandparent where the subsequent generations are born outside of the UK.
The most common exception to this general rule is where the parents were married BEFORE 1 January 1949, and applies in the following situation:
- the applicant was born after 01.01.1949;
- the applicant's paternal grandfather (i.e. father's father) was born in the UK (which includes Scotland and Northern Ireland); AND
- the marriage of the applicant's parents must have taken place before 01.01.1949;
In such a situation, British nationality flowed from the UK-born paternal grandfather to his son (your father), and through to his son's wife (your mother) through marriage before 1949. Recent changes to the law to remedy gender discrimination in the past now means that your mother became British "otherwise than by descent", with the right to pass British nationality to her children (you).
If your parents were NOT married before 1949, then there may still be other opportunities for you to claim British nationality. For example, you should look into whether the following apply in your situation:
1) your father was born in the Transvaal (a province in South Africa) between 1881 and 31 August 1900 when it was a British Protectorate;
2) your maternal grandfather (mother's father) was born in the UK;
3) your father was in Crown Service at the time of your birth;
4) your father was born in a former British territory or country where the UK exercised control; OR
5) your mother registered as a British citizen on the basis of her marriage to your (British) father, and this registration took place before your birth.