Child born abroad: British citizenship by descent

If you were born in the UK and your child is born abroad, they're almost certainly British already. If you were born abroad yourself, it gets more interesting.

The short version

A child born outside the UK on or after 1 July 2006 is automatically British if a parent was British at the birth and that parent could pass it on, typically because they were born or adopted in the UK or naturalised there [1].
Citizenship by descent usually stops after one generation born abroad. A British-by-descent parent generally can't pass it on automatically [2].
Those children may be able to register as British using form MN1 while under 18. The fee is £1,000 [1].
Registering the birth with the UK is optional: it costs £150, and you don't need it for a passport [3].
The UK allows dual nationality, but your child's other country may not, and British dual nationals need a UK passport to enter the UK [4].

Is your child automatically British?

Citizenship law cares about two dates: when your child was born, and how you became British. For children born outside the UK on or after 1 July 2006, GOV.UK says your child is automatically British if all of these apply [1]:

Their mother or father was a British citizen when they were born.
That parent could pass citizenship on. GOV.UK gives three cases: the parent was born or adopted in the UK, was granted citizenship on their own application (naturalised or registered), or was a Crown servant abroad when the child was born, such as a diplomat or in the armed forces [1].

So a Mancunian who moved to Melbourne has a British baby automatically. Nothing to apply for, no certificate needed. The child just is British, and a passport proves it.

Your situation	Is your child born abroad British?
You were born in the UK	Yes, automatically [1]
You naturalised or registered as British	Yes, automatically [1]
You were born abroad to a British parent (British by descent)	Not automatically. Your child may be able to register (see below) [1][2]
You were a Crown servant abroad at the birth	Yes, automatically [1]

If your child was born before 1 July 2006, especially to a British father who wasn't married to the mother, different rules apply. GOV.UK has separate pages for births between 1983 and June 2006 and before 1983, and some people in those groups can register now [2].

Citizenship by descent: the one-generation rule

GOV.UK puts it plainly: citizenship is normally passed automatically to one generation born abroad. Children born abroad to a British parent may be British, but their own children generally won't be [2].

Take a family who left for Toronto. Their daughter, born there, is British by descent. If she has a baby in Toronto, that baby isn't automatically British. It's a bit of a minefield, and the gap usually shows up years later when someone tries to get a first passport.

Registering a child of a British-by-descent parent

For a child born on or after 1 July 2006, there are two main routes. Under both, the child must be under 18 and have had a British parent at the birth [1]:

The parent lived in the UK before the birth. The British parent lived in the UK for at least three years at some point before the child was born, with no more than 270 days outside the UK in that period. That parent's own British parent must also have been able to pass on citizenship [1].
The family lives in the UK now. The child has lived in the UK with their parents for the three years before applying, and neither child nor parents spent more than 270 days outside the UK in that time [1]. If the parents have separated, only one needs to have lived with the child, but both must consent [1].

The application uses form MN1, online or by post. The fee is £1,000, and a fee waiver may be available for under-18s who can't afford it [1]. Applicants give fingerprints and a photo at a biometrics appointment [1].

The practical upshot: if you're British by descent and thinking about where to have children, a spell in the UK before or after the birth can make a big difference. Apply before your child turns 18, because these routes close on their 18th birthday.

Registering the birth with the UK (optional)

You must register the birth in the country where your child was born. Registering it with the UK as well is optional: "You do not need to do this" [3]. It's available for children born on or after 1 January 1983 [3].

If you do, the FCDO's Overseas Registration Unit records the birth with the General Register Office (or the National Records of Scotland), and you can order a consular birth registration certificate [3]. It's handy if the local certificate is in another language or a format UK officials don't recognise easily.

Item	Fee [3]
Registering the birth	£150
Each consular birth registration certificate	£50
Return postage of your documents	£6 to £42, depending on country
Processing time	At least 5 working days, plus postage

Apply through GOV.UK's online "register a birth abroad" service. For twins or more, or if you can't apply online, the page gives an FCDO email address [3]. It's not proof of citizenship and it isn't needed for a passport [3].

Your child's first British passport

The passport is what actually proves your child is British. You apply through the same HM Passport Office overseas service as for renewals [5]. From 8 April 2026 a child's passport applied for online from overseas costs £75.50 [6].

A first child passport needs more than a renewal. Typically you'll be asked for:

The child's full local birth certificate, showing the parents' details, with a translation if it isn't in English.
Evidence that a parent was British at the birth, usually that parent's passport and, if they were born abroad themselves, their own birth certificate and their parent's details.
The parents' marriage certificate, where it helps show the link to a British father.
A digital photo of the child that meets HM Passport Office's photo rules, which are a little more forgiving for babies.
A countersignatory or referee where the service asks for one.

The online service tells you exactly which documents to send. First applications take longer than renewals, so don't book a Christmas trip to see Nan until it's arrived. Our guide to renewing a British passport from abroad covers timings, fees and emergency travel documents.

Dual nationality: the basics

Most children born abroad to a Brit end up with two nationalities. The UK is relaxed about it: dual citizenship "is allowed in the UK", and you don't need to apply for it [4]. Other countries are less relaxed, and "many countries do not accept dual citizenship" [4], so check with your other country's embassy. Some make you choose at 18, or treat a voluntary second nationality as giving up theirs.

Four practical rules:

Enter the UK on a British passport. British dual nationals can't get an electronic travel authorisation (ETA), so they need a valid UK or Irish passport, or a certificate of entitlement in their other passport [4]. Don't let your child's UK passport lapse.
Consular help stops at the other border. In the country of your other nationality, you generally can't get British diplomatic help [4].
Check before you assume. The Home Office doesn't keep a record of everyone who's automatically British, so check status before travelling [4].
Renouncing is possible. An adult (or a married under-18) who has, or is about to get, another nationality can make a declaration of renunciation, the form known as RN1, by post if you live outside the UK and the Crown Dependencies [7][8]. Only do this if your other country requires it, because getting British citizenship back later isn't automatic.

If your partner is Australian, our sister site ExpatCooee explains how Australian citizenship by descent works for babies born overseas.

A baby born abroad: is your child British, and what do you need to do?