British Citizenship by Descent
British citizenship law has a unique 'otherwise than by descent' rule that limits how citizenship transmits to generations born outside the UK. A person born abroad to a British citizen parent who was themselves born or naturalized in the UK is automatically British 'by descent.' However, that British 'by descent' citizen generally cannot transmit British citizenship to their own child born abroad — creating a one-generation-abroad cutoff. There are some pathways for grandchildren and further descendants, but they typically require discretionary applications and are not automatic. The UK has no restrictions on dual citizenship.
Michael Soucek·Last reviewed: October 2026
Educational information only — not legal advice. Always verify requirements with the relevant government authority, consulate, or registry office.
Current passport design
© Wikimedia Commons
Who qualifies for British citizenship by descent
Automatic citizenship: a person born abroad to a parent who is British 'otherwise than by descent' (born or naturalized in the UK) is automatically British 'by descent.' One-generation cutoff: a person born abroad to a parent who is themselves British 'by descent' (born abroad to a British parent) is NOT automatically British. There is no grandparent route. Registration is possible in specific cases: Section 3(2) and 3(5) for children (applied for before age 18, with UK residence conditions), Section 4C for people born before 1983 to British mothers, and Sections 4F–4I for children of unmarried British fathers born before July 2006. Registration under these still gives citizenship by descent, so it does not pass to a further generation born abroad.
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'By descent' versus 'otherwise than by descent' — the whole system turns on this
British nationality law splits citizens into two classes. Someone born or naturalised in the UK is British 'otherwise than by descent'. Someone born abroad to a British parent is British 'by descent'. The distinction, set by the British Nationality Act 1981 (in force 1 January 1983), controls how far citizenship travels.
A person born abroad to a parent who is British 'otherwise than by descent' is automatically British by descent. But a person born abroad to a parent who is themselves British 'by descent' is not automatically British at all. That is the one-generation-abroad cutoff: UK-born or UK-naturalised grandparent, yes; a grandparent who was themselves only British by descent, generally no automatic claim.
Routes for grandchildren and beyond are discretionary, not automatic
There are registration provisions — Section 3(2) and 3(5) of the 1981 Act for children of British-by-descent parents, and the historical-unfairness provisions — Section 4C for people born before 1983 to British mothers, and Sections 4F–4I for children of unmarried British fathers born before July 2006 — but each has conditions, and registration under them still gives citizenship by descent. Section 3(2) registration for a grandchild has to be completed before the child turns 18; miss that window and the only remaining option is a discretionary adult application.
Pre-1983 gender rules can be the fix — or the obstacle
The British Nationality Act 1948, which the 1981 Act replaced, only transmitted citizenship through fathers. A child born before 1 January 1983 to a British mother who was not herself British 'by descent' may have a claim through special registration pathways that correct the old discrimination. If your British line runs through a woman and a pre-1983 birth, this is worth investigating specifically rather than assuming the maternal line is dead.
Fees, timeline, dual citizenship
The UK charges some of the highest citizenship registration fees anywhere: over £1,200 for an adult registration as of 2024, £1,214 for a child, plus £82.50 to £122.50 for the passport afterwards. A straightforward registration totals roughly £1,300 to £1,600.
Registration for someone automatically entitled takes 6 to 12 months; Section 3 grandchild registrations 6 to 18 months; discretionary applications 12 to 24 months or more. The UK places no restriction on holding other nationalities — British citizens can hold any number of other passports without affecting their British status.
British requirements at a glance
- At least one parent is British 'otherwise than by descent' (born or naturalized in the UK) — this creates automatic British-by-descent citizenship for a child born abroad
- For grandchildren: register under Section 3(2) or 3(5) of the British Nationality Act 1981 before age 18, or apply under Home Secretary's discretion
- For adult grandchildren: discretionary application with justification of entitlement
- Application at HM Passport Office or UK Visas and Immigration (UKVI), or via the nearest British consulate
- The UK has no restrictions on holding multiple citizenships
Documents for a British claim
- 1Applicant's birth certificate
- 2British parent's proof of British citizenship and evidence they are 'otherwise than by descent' (their UK birth certificate or UK naturalization certificate)
- 3For transmission through a by-descent parent: that parent's birth certificate plus the grandparent's UK birth or naturalization certificate
- 4Marriage certificates for relevant couples in the chain
- 5Apostilles on foreign documents
- 6Application form: UKF for adult registration; MN1 or T for children's registration
British processing times
Registration for those automatically entitled (British by descent): 6–12 months via UKVI or consulate. Section 3 grandchild registrations: 6–18 months. Discretionary applications: 12–24+ months. British naturalization (5 years legal residency): 18–36 months to process.
Where British claims go wrong
- One-generation cutoff: if your British parent was themselves born abroad to a British parent (i.e., they are British 'by descent'), you are NOT automatically British — only a UK-born or UK-naturalized grandparent's citizenship creates entitlement
- Pre-1983 gender rules: the British Nationality Act 1948 only transmitted citizenship through fathers; children born before January 1, 1983 to British mothers who were not themselves British 'by descent' may need to apply through special registration pathways
- Section 3 deadline: grandchild registration under Section 3(2) must be completed before the child turns 18; missing this window requires a discretionary application as an adult
- High fees: the UK charges some of the highest citizenship registration fees in the world (over £1,200 per adult as of 2024), which have been subject to legal challenge
Official British government sources
British citizenship FAQ
Can I get British citizenship through a grandparent?
Automatically, only if a parent is British 'otherwise than by descent' — that is, born or naturalised in the UK. If your British parent was themselves only British 'by descent' (born abroad to a British parent), you are not automatically British; grandchild routes then exist but are discretionary registration applications, not entitlements, and Section 3(2) must be used before age 18.
What does 'British by descent' versus 'otherwise than by descent' mean?
'Otherwise than by descent' means born or naturalised in the UK. 'By descent' means born abroad to a British parent. A 'by descent' citizen generally cannot pass British citizenship automatically to their own child born abroad — the one-generation-abroad cutoff.
My British grandmother's child was born before 1983 — does the maternal line count?
It may. The pre-1983 law only transmitted citizenship through fathers. Children born before 1 January 1983 to British mothers who were not themselves 'by descent' can sometimes claim through special registration pathways created to correct that discrimination.
Does the UK allow dual citizenship?
Yes, with no restrictions. British citizens may hold any number of other nationalities without affecting their British citizenship.
How much does British citizenship registration cost?
Over £1,200 for an adult registration as of 2024 (£1,214 for a child), plus £82.50 to £122.50 for the passport. A straightforward registration totals roughly £1,300 to £1,600 — among the highest citizenship fees in the world.
British nationality law
British citizenship is governed by the British Nationality Act 1981 (BNA 1981), which came into force on January 1, 1983. Section 2 creates the automatic British-by-descent status. Section 3 allows registration of children of British-by-descent parents. The 'otherwise than by descent' distinction is the key mechanism limiting multi-generation transmission. The BNA 1981 replaced the British Nationality Act 1948.
Dual citizenship in the UK
The UK has no restrictions on dual or multiple citizenship. British citizens can hold any number of other nationalities without affecting their British citizenship. Equally, foreign nationals who acquire British citizenship are not required by UK law to renounce their other nationality, though some countries' own laws may require renunciation when their citizens acquire British citizenship.
British application costs
Registration as a British citizen (adult): £1,206 as of 2024 (subject to challenge and change). Registration for a child (under 18): £1,214. Passport application after registration: £82.50–£122.50. Apostilles: £15–£30 per document. Total for a straightforward registration: approximately £1,300–£1,600.
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Start the CheckerAbout the author
Michael Soucek— Claimed Hungarian citizenship by descent firsthand
Founder & Researcher, Heritage Passport Finder
I built Heritage Passport Finder after going through the process of claiming Hungarian citizenship by descent myself. Tracing my family's records and working out what actually qualified turned into a genuine obsession with how citizenship-by-descent law works across Europe, so I started gathering what I learned in one place. I'm not a lawyer, and I don't treat these guides as the final word — citizenship law changes constantly and differs by country, so every page points to official sources and I recommend confirming your own case with the relevant consulate or an immigration attorney. What I can offer is a clear map of the landscape, drawn from official sources and the experience of someone who has actually been through it.