Registration of adults as British citizens

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In a limited number of scenarios, registration as a British citizen is available to persons over 18. An application for registration can be made from the UK or from overseas and we are happy to help with the application whether you are based in the UK or abroad.

This page summarises the circumstances in which registration is available for adults. If these scenarios are not applicable to you, an alternative route you should consider would be naturalisation as a British citizen.


When women could not pass citizenship by descent

It wasn’t until 1983 that British women would pass British citizenship to their children born outside the UK.

This historical discrimination against women was amended by s. 4C of the British Nationality Act 1981.

There is another – less common – aspect to the rule. Women who were British by descent – i.e. born outside the UK to a British-born father could not register their children as British citizens in the same way as was open to British-by-descent men. As a result, registration is available in some double descent scenarios where there is a British grandfather on the maternal side.

Application for registration under this provision can be made from the UK or from abroad. They are made free of charge with the exception of a biometric appointment and ceremony invitation. There is no residence requirement and since 25 July 2019 good character requirement does not apply.

Applicants for registration under this section are granted citizenship by descent.

There are two guidance documents for this type of registration – UKM guide and Children of British parents guidance.

The requirements can be summarised as follows:

  • The Applicant has to have been born before 1 January 1983;
  • The Applicant’s mother should have been Citizen of the UK and Colonies (by birth or by descent);
  • Either the applicant’s mother or the applicant’s maternal grandfather should have been born, adopted, naturalised or registered in the UK.

Before the British Nationality Act 1981 came into force, British women could not pass British citizenship to their children in the same way as men. The BNA came into force on 1 January 1983 and provided for British citizenship to be passed by men and women alike.

The legal deficiency which existed prior to 1983 was corrected with a retrospective effect in 2003 by the introduction of s. 4C to the British Nationality Act 1981. This section provides for registration of persons born to British mothers outside the UK before 1 January 1983.

Further clarification on the law governing transmission of British citizenship by descent through the female line comes from the Supreme Court in the case of Romein. The court considered whether a woman who was a British citizen by descent, i.e. born outside the UK to a British-born father, could pass British citizenship to her children born outside the UK.

The Supreme Court confirmed that registration under s.4C should be allowed in this scenario because pre-1983 nationality law allowed a male British citizen by descent to pass his British citizenship to a male child by registering this child at a British consulate within one year of birth. Since girls could not be registered as British citizens within one year of birth simply because the law only allowed for registration of boys, the Supreme Court found that the retrospective amendments to the legislation under the British Nationality Act 1981 should be extended to persons born to British-by-descent mothers waiving the requirement to have registered the child with the British consulate within one year of birth.

As a result, women born abroad to British citizens by descent are in a somewhat better position than men. But that’s what we call positive discrimination.

Registration of persons born to unmarried fathers

Another scenario permitting registration of adult persons as British citizens is where the person was born to a British father but did not take British nationality from the father because the parents were not married. This historic discrimination against illegitimate children was mitigated by s. 4G of the British Nationality Act.

What you will need to demonstrate:

  • Evidence of a relationship – a birth certificate issued within the first year of birth showing the names of both parents. If this is not available, other evidence proving paternity, such as DNA test results from an approved DNA test provider, a court order, or other evidence to prove you are related as claimed.
  • Evidence of your father’s British citizenship – this can be a full birth certificate, certificate of naturalisation, passport, or evidence that he was settled in the UK at the time of your birth if you were born in the UK after 1 January 1983.
  • Good character requirement does not apply from 25 July 2019.


You can apply for registration from the UK or from abroad. The type of citizenship you will be granted will depend on whether you were born in the UK or abroad. It will be citizenship other than by descent if you were born in the UK or citizenship by descent if your were born outside the UK.

Persons born in the UK after 1983 who were not British by birth but have lived in the UK for the first ten years of life

From 1 January 1983, not every person born in the UK is a British citizen.

Normally, children born in the UK to parents who have a limited right of residence, would be registered as British citizens when one of the parents becomes settled. However, if for whatever reason this didn’t happen, there is an independent right for registration of any person who was born in the UK and lived in the UK for the first ten years after birth.

This application can be made both by children and adults.

In practical terms, it may be more difficult to collect information relating to the first years of your life when you are an adult. But the application can be made at any time and there is no cut off point.

What you will need to demonstrate:

  • You were born in the UK on or after 1 January 1983;
  • You didn’t acquire British citizenship at birth – you will need evidence of nationality and immigration status of your parents;
  • You were resident in the UK throughout the first ten years of your life and were not out of the country for more than 90 days in each year; you would normally be required to show your school records and registration with a GP; and possibly nursery records or records of your parents’ residence in the UK during the relevant period.
  • You are of good character.


This registration is under s.1(4) of the British Nationality Act 1981. The application is made online or on Form T. The application can be made in the UK or abroad.

Evidence in support of the application

  • Birth certificate showing the names of both parents;
  • Documents showing immigration status of the parents or allowing the Home Office to make the necessary checks;
  • Evidence of residence – passport or travel document if available showing entry and exit stamps, medical records, child’s red book (personal health record), doctors’ letters, nursery letters; letters from school confirming years of attendance.

Discretion to disregard excessive absences

Under s. 1(7) of the British Nationality Act, The Secretary of State has discretionary power to disregard excessive absences. 

Details are given in the policy guidance document: the decision-maker is expected to waive excess absences if the number of days absent from the UK in any one of the 10 years does not exceed 180 days and the total number of days over the 10 year period does not exceed 990 days. Beyond this, discretion is exercised if absences were due to serious illness or circumstances beyond the family’s control.

British citizenship for British Nationals (Overseas) - registration by entitlement on grounds of residence in the UK

British Nationals (Overseas) can be registered as British citizens under s. 4(2) of the British Nationality Act 1981 on grounds of residence in the UK.The requirements are:
  • lawful residence in the UK for five years before the date of the application with total absences during this period not exceeding 450 days;
  • the number of absences from the UK in the last 12 months should not exceed 90 days;
  • the applicant should have held indefinite leave to remain or settled status for 12 months before the date of the application;
  • presence in the UK at the beginning of the five year period prior to the date of the application;
  • Good character requirement applies and two referees have to be provided for the application.
These requirements are very similar to naturalisation requirements but there are some marginal advantages of registration. Unlike naturalisation, registration under this section is a matter of entitlement, not discretion. Although good character requirement applies, there is an expectation that immigration offences of more than five years are not taken into account.

Historical unfairness and special circumstances

In June 2022, Nationality and Borders Act 2022, added a new provision to the British Nationality Act 1981 allowing for registration of adults as British citizens if, in the opinion of the Secretary of State, they would have been able to become a British citizen but for historical legislative unfairness, an act of omission of a public authority or exceptional circumstances relating to the applicant.

According to s. 4L of the 1981 Act, “Historical legislative unfairness” includes circumstances where the applicant would have become, or would not have ceased to be, a British subject or a British citizen, if males and females were treated equally under applicable legislation, or if children of unmarried partners were treated in the same way as children of married couples, or did not discriminate against children whose mother was married to a person who was not their natural father.

To an extent, these provisions consolidate the developments in case law and repeat provisions already existing under s. 4C of the 1981 Act. However, general reference to historical discrimination makes the provision wider, even in relation to discrimination against women. 

Before 1948, British women who married foreign nationals and left the UK to live overseas would automatically lose their British subject status. They could not pass British citizenship to their children and the claim to British citizenship of their grandchildren or great grandchildren was too remote for the previously enacted provisions rectifying historical discrimination.

It is not totally clear if historical discrimination that the new provision aims to correct is limited to unequal treatment of women. Historical discrimination against nationals of former British colonies, i.e. Commonwealth citizens, denied them equal treatment if compared to non-Commonwealth citizens. For example, registration of British citizenship for children born in double descent was only open outside the Commonwealth. 


Not sure if you are entitled to be registered as a British citizen?

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Last updated on 11 August 2023

Last updated on 11 August 2023

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