Tax Implications of British Citizenship

UK tax and citizenship

The UK tax system is based on tax residence, not citizenship. This means that your tax obligations are determined by where you live, not by your nationality. Becoming a British citizen does not, by itself, create any new tax liabilities or change your existing tax position.

If you have been living and working in the UK on a visa, you have already been paying UK tax as a tax resident. After citizenship, this continues as before.

The rules on tax residence are set out on the GOV.UK tax residence page.

Worldwide income

UK tax residents are taxed on their worldwide income. This includes:

• Employment income from UK and overseas sources
• Self-employment income
• Rental income from property anywhere in the world
• Investment income (dividends, interest, capital gains)
• Pension income from UK and overseas pensions

This obligation exists regardless of your citizenship. It applied when you were on a visa, and it continues after citizenship. For those still on a Skilled Worker visa or Spouse visa, the same rules apply.

Double taxation agreements

If you are a dual national with income or assets in another country, you may be concerned about paying tax on the same income in both countries. The UK has double taxation agreements with many countries. These agreements typically provide that:

• Each type of income is taxed primarily in one country
• If tax is paid in both countries, you can claim relief to avoid paying twice
• The agreement determines which country has the primary right to tax specific types of income

Check the GOV.UK tax treaties page to see whether your other country of nationality has an agreement with the UK, and what it covers.

What replaced the remittance basis

The remittance basis, under which non-domiciled UK residents paid UK tax on foreign income only when they brought it into the UK, was abolished on 6 April 2025. HMRC says that from that date domicile was replaced by tax residence as the connecting factor in the tax system, and all UK residents are taxed on their worldwide income and gains as they arise.

In its place is the 4-year foreign income and gains regime. You can claim under it if you are UK resident under the statutory residence test and are within your first 4 years of UK residence after at least 10 consecutive tax years of non-residence. Claiming it means giving up your tax-free allowances for Income Tax and Capital Gains Tax, and the Married Couple’s, Marriage and Blind Person’s Allowances. The claim is made on a Self Assessment tax return, and you can choose which sources to claim relief on.

Because the test is about residence, not nationality, becoming a British citizen does not affect whether you can claim it, and neither does holding indefinite leave to remain. A separate temporary repatriation facility applies to foreign income and gains that arose before 6 April 2025.

Your other nationality

Some countries tax based on citizenship rather than residence. The most notable example is the United States, which taxes its citizens on worldwide income regardless of where they live. If you hold citizenship of such a country in addition to British citizenship, you may have reporting obligations in both countries.

Most countries tax on the basis of residence rather than citizenship, so keeping a second nationality does not by itself create a tax bill there. What does matter is whether you still have income, property or assets in that country. The UK treaty list above is the place to check what each agreement covers.

Our country guides for Nigerian, Pakistani and South African nationals cover the nationality side of holding two citizenships.

Reporting foreign income

If you have foreign income, you must report it on your Self Assessment tax return. The immigration health surcharge you paid during your visa period was a charge for healthcare access, not a tax, and is separate from this. Income to report includes:

• Rental income from property abroad
• Foreign bank interest
• Overseas pension income
• Capital gains on foreign assets
• Foreign employment income

You report foreign income through the Self Assessment system. If you have not been reporting foreign income, rectify this as soon as possible. HMRC has the power to investigate and impose penalties for undeclared income.

Inheritance tax

Inheritance tax also moved from domicile to residence on 6 April 2025. HMRC’s guidance on inheritance tax for long-term UK residents says you are a long-term UK resident if you have been resident in the UK for at least 10 of the 20 tax years immediately before the tax year in which the chargeable event, including death, arises. A long-term UK resident’s worldwide assets are within the scope of inheritance tax. This replaced the previous deemed domicile test of 15 of the previous 20 tax years.

Someone who has been a long-term UK resident and then leaves stays within scope for between 3 and 10 years, depending on how long they were resident. Citizenship is not part of the test either way.

Estate planning matters for dual nationals with assets in more than one country. Our DIY vs solicitor guide covers when to get professional help.

National Insurance and pension

Your National Insurance contributions are not affected by citizenship. If you have been contributing to the UK system, your state pension entitlement continues to build regardless of your nationality. Citizenship simply ensures you can remain in the UK permanently to claim your pension.

Getting professional advice

If you have income, assets, or tax obligations in more than one country, professional tax advice is strongly recommended. A cross-border tax specialist can help you:

• Understand your reporting obligations in both countries
• Claim relief under double taxation agreements
• Plan your affairs to minimise unnecessary double taxation
• Ensure you are compliant with all applicable tax laws

Questions and answers