Adults may become British citizens by naturalisation or registration, depending on their individual circumstances and nationality history.
Naturalisation is the usual route for adults who have settled permanently in the UK. Registration is a separate route available to people who qualify under a specific provision of British nationality law.
Registration may be relevant, for example, to certain Irish citizens, people born in the UK who meet particular residence requirements, people with a British parent who missed out on citizenship under previous nationality laws, people who hold another form of British nationality, and those affected by historical legislative unfairness, an act or omission by a public authority, or exceptional circumstances.
The requirements, fees and legal consequences differ between naturalisation and registration. It is therefore important to establish first whether the applicant:
For settled adult migrants who do not qualify for registration, naturalisation is normally the appropriate route. Its requirements cover residence, absences, lawful immigration history, freedom from immigration time restrictions, knowledge of language and life in the UK, and good character.
Naturalisation is discretionary. Meeting the basic requirements does not create an automatic entitlement to British citizenship, and the Home Secretary retains judgment when deciding the application.
The standard naturalisation route is generally available to adults aged 18 or over who:
A person who is married to, or in a civil partnership with, a British citizen may apply under the three-year residence route. They must still be free from immigration time restrictions on the date of application, but they do not normally need to have held settlement for 12 months.
Marriage or civil partnership to a British citizen does not, by itself, make a person eligible for citizenship.
Adult registration may be available under a number of specific provisions, including for:
This is not an exhaustive list. Registration is not simply an alternative to naturalisation and cannot be selected by preference. The applicant must qualify under a particular provision of the British Nationality Act 1981 or other applicable nationality legislation.
Some registration routes provide an entitlement to citizenship where all the statutory requirements are met, while others remain discretionary. The residence, good-character, language and knowledge requirements differ depending on the particular route.
The standard requirements include:
Discretion may be exercised in relation to some residence and absence requirements, but this is not automatic and must be supported by appropriate evidence.
The requirements for registration depend entirely on the statutory provision under which the application is made.
Depending on the route, an applicant may need to establish:
Registration does not always require the applicant to hold Indefinite Leave to Remain or settled status. The English-language and Life in the UK requirements also do not apply to every registration route.
The legal basis should therefore be identified before the application form and evidence are prepared.
Naturalisation is the usual route for adult migrants who have settled in the UK and completed the required residence period. It is always discretionary.
Registration is available only where the applicant qualifies under a specific provision of nationality law. Some registration routes provide an entitlement to citizenship, while others are discretionary.
The requirements for naturalisation should not be applied automatically to a registration application. For example, some registration routes do not require settlement, an English-language qualification or the Life in the UK test.
Possibly. British nationality can be acquired automatically by birth, descent, adoption or under historical nationality legislation.
A person who is already British should not apply for naturalisation or registration. They may instead need to apply for a first British passport or obtain other evidence of their citizenship.
This should be checked carefully before paying an application fee.
Under the standard five-year route, applicants must normally have been free from immigration time restrictions for at least 12 months before applying. This usually means waiting 12 months after receiving Indefinite Leave to Remain or settled status.
A person who is married to, or in a civil partnership with, a British citizen does not normally have to wait 12 months after receiving settlement. However, they must be free from immigration time restrictions on the date of application and satisfy the three-year residence requirements.
Not in every case. Registration is based on the requirements of the particular statutory provision.
Some registration routes depend on birth, parentage, another form of British nationality or historical unfairness rather than the applicant holding Indefinite Leave to Remain or settled status.
For naturalisation, you must normally have been physically present in the UK, the Isle of Man or the Channel Islands on the exact date five years before the Home Office receives your application.
For naturalisation as the spouse or civil partner of a British citizen, the corresponding period is three years.
Some registration routes also contain an exact-date physical-presence requirement. For example, the registration route for qualifying Irish citizens requires physical presence in the UK at the beginning of the relevant five-year period.
Under the standard five-year route, the normal limits are 450 days outside the UK during the five-year qualifying period and 90 days during the final 12 months.
Under the three-year route for spouses and civil partners of British citizens, the normal limits are 270 days during the three-year period and 90 days during the final 12 months.
The Home Office has discretion to overlook excess absences in appropriate circumstances, but the outcome depends on the number of absences, the applicant’s connections with the UK and the reasons for the travel.
Registration routes may have different absence requirements. The rules for the particular registration provision must be checked separately.
The assessment can include criminal convictions, cautions, pending prosecutions, immigration breaches, deception, dishonesty, tax and financial matters, bankruptcy, unpaid council tax, fraud involving public funds and other conduct.
The list is not exhaustive. Applicants must provide honest and complete information, including information about relevant matters that occurred outside the UK.
Good character is required for naturalisation and for many adult registration routes, although the precise legal position depends on the registration provision being used.
It depends on the nature of the breach, the citizenship route and the individual circumstances.
The Home Office’s current policy states that citizenship applications made on or after 10 February 2025 will normally be refused where the applicant previously entered the UK illegally, regardless of how long ago the illegal entry occurred. The guidance allows individual circumstances and relevant exceptions to be considered, but this is a significant area of risk.
Other matters, such as overstaying, working in breach of conditions or previous deception, must also be assessed carefully. Concealing a relevant issue can create an additional and potentially more serious good-character concern.
Applicants can normally meet the requirement by passing an approved speaking-and-listening test at level B1 or above, holding an eligible academic degree taught or researched in English, or being a national of an accepted majority English-speaking country.
Applicants aged 65 or over, or those unable to meet the requirement because of a qualifying long-term physical or mental condition, may be exempt.
An approved B1 qualification previously accepted for a settlement application can normally be used again for citizenship, even if the test certificate has since expired.
The English-language requirement does not apply to every registration route.
No. If you passed the Life in the UK test for your settlement application, you do not need to take it again for naturalisation.
Applicants aged 65 or over and applicants with a qualifying long-term physical or mental condition may be exempt.
The Life in the UK test is not required for every registration application.
The fee depends on whether the application is for naturalisation or registration and, for registration, the particular statutory route.
As at 26 August 2026, the standard adult-registration application fee is £1,540, with a £130 citizenship-ceremony fee added, making the total £1,670.
Different fees apply to certain registration routes. A qualifying Irish citizen pays £723 for the application and £130 for the citizenship ceremony, making the total £853. Applications using forms UKM, UKF, BOTC(F) or BOTC(M) attract only the £130 ceremony fee.
For applications based on historical legislative unfairness, an act or omission by a public authority, or exceptional circumstances, no application fee is payable where the person would otherwise have acquired British citizenship automatically. However, the adult ceremony fee remains payable. If the person would only have been eligible to apply for registration or naturalisation, rather than acquiring citizenship automatically, the relevant application fee and ceremony fee must still be paid.
Fees change periodically and should always be checked before submission.
The Home Office usually aims to decide citizenship applications within six months, although complex cases or applications requiring additional checks can take longer.
Eligible applicants may be able to pay an additional £500 for a priority service, which usually provides a decision within 30 working days. The service does not guarantee a decision within that period where further information or additional checks are required.
The super priority service is not available for citizenship applications.
A person applying from within the UK can generally travel using a valid passport and evidence of their valid UK immigration status while the application is pending.
However, a citizenship application does not extend or replace immigration permission. A naturalisation applicant must maintain valid immigration status until the application has been decided and the citizenship ceremony has been completed.
Applicants must also comply with biometric-enrolment instructions, which will usually require action within 45 days of submitting the application.
Approval of the application does not, by itself, make an adult applicant a British citizen.
An adult will normally become a British citizen when they attend the citizenship ceremony and make the required oath or affirmation and pledge. They will then receive their naturalisation or registration certificate.
The certificate is evidence of citizenship but is not a travel document. A separate British passport application, or an application for a certificate of entitlement to the right of abode, is required for travel as a British citizen.
This depends on the legal provision under which citizenship is acquired.
A person naturalised in the UK will normally become a British citizen otherwise than by descent. Registration may result in citizenship either by descent or otherwise than by descent, depending on the particular route.
This distinction can affect whether British citizenship is automatically passed to a child born outside the UK.
The UK permits dual nationality. However, whether you can retain your existing nationality depends on the law of the other country.
Some countries do not allow dual nationality or may impose conditions or consequences. The position should be checked before applying, particularly where nationality affects property ownership, inheritance, taxation or military-service obligations.
