Naturalisation as a British Citizen: Form AN Guide and Application Support

Naturalisation is the formal legal process by which an adult migrant acquires British citizenship. It is governed by the British Nationality Act 1981 and is the standard route for most adults who have lived and worked in the UK and now hold Indefinite Leave to Remain (ILR), Indefinite Leave to Enter, or EU Settled Status. Unlike registration, which applies to children and some other specific groups, naturalisation requires demonstrating that you have built a genuine life in the UK over the qualifying period.

Naturalisation is not an entitlement. The Home Secretary has discretion to grant or refuse citizenship, and applications are refused where requirements are not fully met. Because the application fee is not refunded on refusal, preparing a thorough and accurate application is essential.

Calculating your absences accurately is one of the most important steps in preparing a naturalisation application, and one of the most common sources of error. The rules are strict:

• Standard 5-year route: No more than 450 days outside the UK in total during the five-year qualifying period, and no more than 90 days in the 12 months immediately before your application date.
• Spouse or civil partner 3-year route: No more than 270 days outside the UK in total during the three-year period, and no more than 90 days in the final 12 months.

The Day One Rule

You must have been physically present in the UK on the exact date that falls five (or three) years before your application date. If you were abroad on that date, even if you returned the next day, your qualifying period has not yet started from the perspective of the application. You must identify a different application date and recalculate.

The Home Office checks travel history through passport records and Border Force data. Some discretion exists for absences that moderately exceed the limits where there are compelling reasons such as serious illness or essential work overseas, but this is not guaranteed and should not be assumed. Work Permit Cloud carries out detailed absence calculations before submission.

Good Character

Every applicant must be of good character. The Home Office assesses:

• Criminal history: all UK and overseas convictions, including spent offences. Minor fixed penalty notices can be relevant depending on how recent they are.
• Immigration compliance: any breaches of immigration law during or prior to the qualifying period, including overstaying, working without permission, or deception. A clean immigration record throughout the qualifying period is expected.
• Tax compliance: the Home Office cross-references applications with HMRC. Outstanding tax debts, late filings, or disputed self-assessment returns can raise concerns.
• Irregular entry: from 10 February 2025, entering the UK by irregular means (by small boat or concealed in a vehicle) will normally result in refusal, regardless of elapsed time.

Complete and honest disclosure is essential. Deliberate omissions can result not only in refusal but in deprivation of citizenship if discovered after it has been granted.

Life in the UK Test

The Life in the UK Test is a computer-based assessment of 24 multiple-choice questions on British history, traditions, law, and values. You must score at least 75% and must book and pass the test before submitting your application. Results are valid for two years. If you passed the test for a previous ILR application and have your reference number, you do not need to sit it again.

English Language

Most applicants must demonstrate English at CEFR Level B1 via an approved Secure English Language Test (SELT), a qualifying degree taught in English, or on the basis of nationality. Age and disability exemptions apply.

Referees

You must nominate two referees on Form AN. Selecting unsuitable referees can delay your application.

• Referee 1: Must be a British citizen, hold a British passport, and be either a professional or aged over 25. Examples: accountant, solicitor, doctor, teacher, or employer (not your immigration adviser).
• Referee 2: Must be a professional of any nationality — such as a civil servant, minister of religion, or recognised professional.

Both referees must have known you personally for at least three years. They cannot be related to you or to each other, cannot live at your address, cannot work for the Home Office, and must not have had a criminal conviction in the past 10 years.

Submitting Form AN

Naturalisation applications are submitted online through the GOV.UK portal using Form AN. The form requires detailed information about your identity, residence and immigration history, travel history (all absences from the UK), employment, criminal and civil matters, and referee details. Supporting documents include identity documents, proof of ILR or Settled Status, Life in the UK Test pass confirmation, English language evidence, and proof of residence.

After submitting the form, you book a biometrics appointment at a UKVCAS service point to provide fingerprints and a photograph. Processing typically takes around six months. While the application is being processed, you retain your current immigration status and can continue living and working in the UK.

The Citizenship Ceremony

When your application is approved, you receive an invitation to attend a citizenship ceremony, which must take place within three months. At the ceremony — usually held at a local council office — you take the Oath of Allegiance and a Pledge of Loyalty to the UK and receive your citizenship certificate. You should then return any BRP you hold and can apply for a British passport.