You can apply to become a British citizen through naturalisation if you meet the relevant criteria which have been set out in the British Nationality Act 1981. This is the most common approach to become a British citizen. This application is decided and granted by the Secretary of State for the Home Office.
The main requirements for naturalisation involve meeting the residence requirement, settled status requirement, good character requirements and the English language test and Life in the UK test requirements.
Naturalisation after holding settlement for 12 months:
You are eligible to apply to naturalise as a British citizen under Section 6(1) of the British Nationality Act 1981, provided you meet the following requirements:
You are aged 18 or over
You are of good character i.e., do not have a serious or recent criminal record, or any adverse immigration history
You are of sound mind
You intend to make the UK your permanent home
You have passed a Life in the UK test
You have met the knowledge of English language test requirements
You have met the residence requirements
In addition, the following residence requirement must usually apply:
You have lived in the UK for at least 5 years prior to your application
You have not spent more than 450 days outside the UK in those 5 years
You have not spent more than 90 days outside the UK in the last 12 months
You had Settlement (also known as indefinite leave to remain/ILR) for the last 12 months; if you are not an EEA citizen
You had Settled Status under the EU Settlement Scheme (also known as indefinite leave to remain) for the last 12 months; if you are an EEA citizen or eligible to apply to the scheme.
Naturalisation as the spouse of a British citizen
A person who is married to a British citizen will be eligible to naturalise as a British citizen under Section 6(2) of the British Nationality Act 1981. If you are married to a British citizen, you will be subject to all of the above requirements however the only difference is:
You do not have to wait 12 months from obtaining ILR to apply for naturalisation.
You are only subject to 3 years residence requirement i.e. should not have spent more then 270 days outside the UK in the last 3 years.
All other requirements apply.
When sending your application, a biometrics appointment will be mandatory to attend. After applying, a decision will usually be made in 6 months, depending on the application some may take longer.
Once you have received your certificate of British Citizenship, you must send your biometrics residence permit back to the Home Office. The UK allows dual nationality for its citizens however, some countries may not. In which case they can revoke your citizenship once you have become British therefore, it is imperative for you to contact your embassy before you decide to apply for naturalisation.