British citizenship - Naturalisation

The rules and processes for becoming a British citizen are slightly different for adults and children. Find out information about naturalising as a UK citizen for those aged 18 and above.

The most common way of becoming British as an adult is through ‘naturalisation’. This page explains the eligibility requirements and how to apply.

Age

You should be 18 years old or above (see page on registration for children under 18 seeking to become British)

Registration: Information on eligibility and how to apply for registration of children under 18 as British nationals

Presence in the UK

You must have been present in the UK exactly 3 or 5 years (depending on whether you are married to a British citizen or not) before you lodge your application. Example: you are not married to a British citizen and you submit your application on 1st June 2024; this means you need to prove you were inside the UK on 1st June 2019. (There are potentially exemptions for this requirement if there are exceptional circumstances).

Residence in the UK

You must show you have been continuously, lawfully resident in the UK for 5 years immediately before lodging your application (NB this can be 3 years in the case of someone who has ILR through being married to a British spouse – please seek further advice if you’re not sure if this applies to you).

This means you have held continuous valid visas throughout the 5 years, and have not broken any immigration laws during that time.

Absences from the UK

You should not have:

  • spent more than 450 days outside the UK during the 5 years before your application (or no more than 270 days outside in the last 3 years, if you're married to a UK citizen)
  • spent more than 90 days outside the UK in the last 12 months

Indefinite Leave to Remain

By the time you apply, you should have held Indefinite Leave to remain (ILR) for at least 12 months (this includes Settled Status under the EU Settlement Scheme). 

Please note the 12-month requirement does not apply if you are married to, or in a civil partnership with a British national.

Good character

Those seeking to become British must prove they are of ‘good character’. In assessing this requirement, the Home Office will look at things like criminality, breaches of immigration law, debt (such as NHS debt or Council Tax arrears) and other matters. Further guidance on how they assess this can be found here:

Nationality: Good character requirement

It’s very important that anything likely to fall under one of these types of behaviour is disclosed on the application form (if not, the application could be refused simply on the basis of not giving a full disclosure).

If you are not sure if you meet the good character requirement, please contact the Staff Immigration Service who can advise further.


Please see our information page on the Life in the UK test and English language requirements for citizenship:

Life in the UK and English language


You can apply online or else using a paper form. Using the online process is recommended as it tends to be quicker and it also means you don’t have to lodge original documents with the Home Office.

Apply for British citizenship by naturalisation

According to current Home Office service standards, most applications will take around 6 months to get a decision – though more complex cases can take longer.


The current application fee for applying under Form AN is £1630; if you are applying online then this needs to be paid at the time the application is lodged. Bear in mind that you need to have been physically present in the UK exactly 5 years prior to the date of application.

Generally you will need to provide the following documents in support of the application – all of these can be scanned and uploaded if you are using the on-line form:

  • Evidence of ID e.g. your current passport and/or BRP
  • Any passports/travel documents that you hold
  • Evidence of ILR e.g. your BRP or decision granting ILR/Settled Status from UKVI
  • Evidence you have lived continuously in the UK for the past 5 years – passports held for that period; failing which official correspondence such as Council Tax bills, utility bills, bank statements etc

Some countries do not allow their nationals to acquire a second nationality e.g. China;  some will only allow a second nationality to be acquired before a certain age. If you have any doubts on this, it’s important that you check the position with the authorities who issued your current passport before applying to become British.

Normally the Staff Immigration Service cannot advise on questions of nationality law relating to other countries; we would encourage staff members to contact the relevant Embassy/Consulate for information on this. We would be happy to sign post staff members where possible.


Contact the Staff Immigration Service

If you have a query on naturalisation, or regarding other British nationality issues, please contact the Staff Immigration Service for further information.

Contact the Staff Immigration Service

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