Dual Citizenship UK 2026 -- Rules, Eligible Countries and Process

Last reviewed: 26 April 2026

Dual citizenship UK in 2026 is a topic of growing interest among British nationals living abroad who are approaching the naturalisation threshold in their country of residence and want to understand the implications for their British passport and UK tax position. The UK’s approach to dual nationality is permissive: the British Nationality Act 1981 does not require British nationals to choose between their British citizenship and a newly acquired foreign nationality. A British national who naturalises as a Portuguese citizen, American citizen, Australian citizen, or French citizen retains their British passport and UK citizenship automatically. For the full tax implications of leaving the UK and establishing residency abroad, see our UK tax residency guide; for how dual citizenship interacts with investment and estate planning, see our UK expat investments guide.

Dual citizenship UK is not the same as dual tax residency. Holding two passports does not make a person tax resident in both countries simultaneously; tax residency is determined by each country’s domestic rules (in the UK, the Statutory Residence Test; in most other countries, physical presence tests or primary home tests). A British national who naturalises as Portuguese retains their British passport but may be solely Portuguese tax resident (having spent more than 183 days in Portugal) and solely Portuguese income tax liable for that year. HMRC’s RDR1 guidance makes clear that citizenship and tax residency are entirely separate determinations; HMRC does not consider foreign citizenship as evidence of non-UK-residency, and it does not consider British citizenship as evidence of UK residency.

UK law: British Nationality Act 1981

The British Nationality Act 1981 (BNA 1981) is the primary legislation governing British citizenship. Under the BNA 1981, British citizenship is not lost by acquiring a foreign nationality; section 12 confirms that a British citizen does not cease to be a British citizen by reason of acquiring another citizenship or nationality. This has been the position since 1948 (when the British Nationality Act 1948 was enacted); the UK has not required renunciation of British citizenship on acquisition of another nationality for more than 75 years. The Home Office at gov.uk/dual-nationality confirms this position: "There’s no rule against having more than one nationality in the United Kingdom." The FCDO publishes guidance on consular assistance; UK nationals who hold dual citizenship may receive UK consular assistance in third countries, but the FCDO notes that if the other country of citizenship considers the person primarily their national, UK consular assistance in that country may be limited (under the Vienna Convention on Consular Relations, a state may decline to provide consular assistance to its own nationals).

Countries that allow dual citizenship with the UK

Over 90 countries worldwide permit dual citizenship with the UK. Major destination countries for UK expats that allow dual citizenship include: USA (US citizenship does not require renunciation of UK citizenship; approximately 125,000 UK nationals naturalised as US citizens between 2015 and 2025 per DHS data); Australia (Australian citizenship law allows dual citizenship; Australian Citizenship Act 2007 s.34 confirms citizens are not required to renounce other nationalities); Canada (Citizenship Act, RSC 1985, permits multiple citizenship); Ireland (Irish Nationality and Citizenship Act 1956 permits dual citizenship; UK nationals of Irish heritage may be eligible for Irish citizenship by descent); Portugal (Portuguese Nationality Act permits dual citizenship); France (French Nationality Code permits dual citizenship); Germany (Staatsangehörigkeitsgesetz, reformed 2024, now permits dual citizenship for most naturalised citizens including UK nationals after 5 years of residence); New Zealand (Citizenship Act 1977 permits dual citizenship); and Singapore (note: Singapore does not permit dual citizenship for adults; Singapore permanent residents who naturalise must renounce other nationalities).

Countries that do not permit dual citizenship

Several countries that are significant expat destinations for UK nationals do not permit dual citizenship, requiring renunciation of British citizenship on naturalisation. India is the most significant: the Indian Citizenship Act 1955 does not permit Indian nationals to hold the citizenship of another country simultaneously; British nationals who acquire Indian citizenship must renounce British citizenship, and Indian nationals who acquire British citizenship automatically lose Indian citizenship under Section 9 of the Citizenship Act. India operates the Overseas Citizen of India (OCI) card as a long-term resident permit for persons of Indian origin who are not Indian citizens (including British nationals of Indian origin); the OCI provides visa-free entry to India and most residency rights except voting and holding constitutional office. Japan (Nationality Act Article 11) requires renunciation of other nationalities by age 22; naturalised Japanese citizens who do not renounce other nationalities risk loss of Japanese citizenship. China does not recognise dual citizenship under the Nationality Law of the PRC (1980); Saudi Arabia does not permit dual nationality. UAE does not permit dual citizenship for UAE nationals, but acquiring UAE citizenship (a rare discretionary process) requires renouncing other nationalities.

How to acquire a second citizenship as a UK national

The routes to a second citizenship for UK nationals abroad vary significantly by country. The most common routes are: naturalisation by residence (after meeting the minimum qualifying period of lawful residence; typically 5 years in EU member states under the EU Long-Term Residents Directive, 5 years in Australia, 3 years in Canada, 5 years in the USA after permanent residence); citizenship by descent (if one or both parents or grandparents were citizens of the country; Ireland allows citizenship by descent from one Irish grandparent under Section 7 of the Irish Nationality and Citizenship Act); citizenship by investment (Portugal Golden Visa or exceptional merit route; Malta Individual Investor Programme; various Caribbean programmes through investment of typically USD 100,000-250,000 in a national fund or USD 200,000+ in real estate); and citizenship by marriage (most countries have a shorter naturalisation period for spouses of citizens). The individual country’s embassy or consulate is the authoritative source for current naturalisation requirements; FCDO publishes a list of country-specific links at gov.uk.

UK tax implications of acquiring a second citizenship

Acquiring a foreign citizenship does not change a UK national’s UK tax residency status. UK tax residency is determined exclusively by the Statutory Residence Test (SRT), introduced by Finance Act 2013 and codified in Schedule 45 FA 2013. A UK national who naturalises as Portuguese and continues to spend more than 183 days per year in the UK remains UK tax resident regardless of their Portuguese passport. A UK national who naturalises as Australian and moves permanently to Australia, spending fewer than 16 days in the UK (satisfying the automatic overseas test), becomes non-UK-resident regardless of which passports they hold. HMRC’s RDR1 guidance is explicit: "Citizenship is not used to determine residence under the SRT." The SRT’s automatic non-UK residence tests and sufficient ties tests are based entirely on physical presence and connections to the UK, not on nationality.

UK IHT exposure for UK nationals with a second citizenship is determined by domicile (for periods prior to 6 April 2025) and by the Finance Act 2025 long-term resident rules (from 6 April 2025 onwards). Prior to the 2025 reform, UK domicile (deemed domicile after 15 of 20 years UK-resident) was the IHT trigger for worldwide estate exposure; from 6 April 2025, the IHT long-term resident test (10 of the prior 20 years UK-resident) applies as an additional trigger. Acquiring a foreign citizenship does not change domicile under traditional English private international law; it may affect the long-term resident tail period calculation if the acquisition involves establishing a permanent home abroad. UK nationals who acquire a second citizenship and leave the UK should take specialist IHT and domicile advice to confirm their IHT exposure position under both the pre- and post-2025 rules. For detailed guidance, see our UK tax residency guide.

Renouncing British citizenship

A British national may renounce their British citizenship voluntarily under section 12 of the British Nationality Act 1981 by completing Form RN (Renunciation of British citizenship) and paying the current fee (£372 as at April 2026, per the Home Office published fee schedule at gov.uk/british-citizenship). Renunciation is irrevocable in most circumstances; it requires the applicant to already hold, or be entitled to acquire, another citizenship, to ensure statelessness does not result. The Home Office processes renunciations at its UK Visas and Immigration operations. UK nationals abroad may renounce through the British consulate in their country of residence. Renouncing British citizenship does not affect UK tax obligations that arise from prior UK residency; a renounced former UK citizen who has recently left the UK may remain within the UK IHT long-term resident tail and may still have ongoing UK CGT obligations on UK assets under the non-resident CGT rules (TCGA 1992 s.1C).

Dual citizenship and security clearance

UK nationals who hold dual citizenship and who have or are seeking UK Government security clearances (DV -- Developed Vetting, SC -- Security Check, or CTC -- Counter Terrorism Check) should declare their dual nationality as part of the vetting process. The UK National Security Vetting (NSV) system, operated by UKSV (UK Security Vetting), requires declaration of all citizenships and passport holdings. Dual citizenship is not an automatic bar to UK security clearance, but clearances are assessed on a case-by-case basis depending on the foreign country of nationality, the nature of the role, and the individual’s connections to the foreign country. UK nationals holding citizenship of certain countries that are classified as higher-security-risk (based on FCDO country assessment) may face additional scrutiny. The FCDO and Home Office publish general guidance; specific clearance questions should be directed to the relevant vetting authority.

This article is for general information only and does not constitute tax, legal, financial or immigration advice. Rules and rates change; verify with the primary sources cited or consult a qualified adviser before acting.

FAQ

Does the UK allow dual citizenship?

Yes. The British Nationality Act 1981, section 12, confirms that British citizens do not lose their citizenship when they acquire another nationality. The UK has permitted dual citizenship since 1948 and does not require renunciation of British citizenship on naturalisation in another country. The Home Office at gov.uk/dual-nationality states there is no rule against holding more than one nationality in the UK. Approximately 90+ countries allow dual citizenship with the UK.

Which countries do not allow dual citizenship with the UK?

Countries that prohibit dual citizenship include India (Citizenship Act 1955; Indian nationals who acquire British citizenship automatically lose Indian citizenship), Japan (Nationality Act Article 11, requires renunciation by age 22), China (Nationality Law of the PRC 1980), and Saudi Arabia. The UAE does not permit dual citizenship for UAE nationals. Singapore does not permit dual citizenship for adults; UK nationals who naturalise as Singaporean must renounce British citizenship. The relevant country’s embassy is the authoritative source for current rules.

Does acquiring a second passport change my UK tax status?

No. UK tax residency is determined by the Statutory Residence Test (Schedule 45 Finance Act 2013), based on physical presence and connections to the UK. Holding a foreign passport does not make a UK national non-UK-resident, and holding a British passport does not make a foreign national UK-resident. HMRC’s RDR1 guidance explicitly states that citizenship is not used to determine tax residence. Only physical presence, work patterns, and UK ties (home, family, work) determine SRT residency status.

How can UK nationals apply for Irish citizenship by descent?

Irish citizenship by descent (Section 7 of the Irish Nationality and Citizenship Act 1956) is available to persons born outside Ireland who have a parent or grandparent who was an Irish citizen at the time of the applicant’s birth. If the qualifying ancestor is a grandparent (not a parent), the applicant must first register on the Foreign Births Register (FBR) at the Irish Department of Foreign Affairs. Applications are submitted to the nearest Irish consulate; processing times were 18-24 months in 2025 due to high demand. Once granted, Irish citizenship confers EU citizenship rights.

How does dual citizenship affect UK Inheritance Tax?

Acquiring a foreign citizenship does not directly change UK IHT exposure, which depends on domicile (for pre-2025 purposes) and on the Finance Act 2025 long-term resident test (10 of the prior 20 years UK-resident, effective from 6 April 2025). Establishing a foreign domicile of choice (requiring a genuine and settled intention to reside permanently in the foreign country) may reduce UK IHT exposure, but this is a complex legal determination unaffected by passport holding alone. Specialist UK IHT and domicile advice is essential for UK nationals who acquire a second citizenship and intend to leave the UK permanently.

Can dual citizens receive UK consular assistance abroad?

UK nationals who hold dual citizenship may receive UK consular assistance from British embassies and consulates abroad. However, the FCDO notes that in the other country of citizenship, UK consular assistance may be limited under the Vienna Convention on Consular Relations, as the host state may consider the person primarily its own national. In practice, UK nationals in difficulty in a country where they also hold citizenship should contact both the UK consulate and local authorities; the FCDO will endeavour to assist but cannot guarantee consular access in all circumstances.

Sources

1. GOV.UK -- Dual citizenship guidance (Home Office) (verified 26 April 2026)
2. British Nationality Act 1981 (legislation.gov.uk) (verified 26 April 2026)
3. HMRC -- RDR1 residence, domicile and remittance basis guidance (verified 26 April 2026)
4. Ireland Department of Foreign Affairs -- Foreign Births Register (verified 26 April 2026)
5. OECD -- International Migration Outlook 2025 (verified 26 April 2026)