Ben Keith en Cosmopolitan: Ciudadanía por descendencia: Lo que un nacimiento en Lisboa revela sobre la ley de nacionalidad

Princess Eugenie gave birth to a daughter at a hospital in Lisbon on 3 August 2026, and the coverage that followed reached for a question our immigration and derecho internacional practice answers most weeks. Does a baby born on Portuguese soil become Portuguese? She does not, and the reason has nothing to do with the family involved. Ben Keith sets out the two statutory frameworks that decided the outcome, and explains why the same rules produce far harsher results for families with no British passport to fall back on.

How citizenship by descent works

Citizenship by descent is nationality acquired through a parent rather than through birth on a particular state’s territory. Section 2(1)(a) of the British Nationality Act 1981 gives British citizenship to a child born outside the United Kingdom where a parent is a British citizen otherwise than by descent. Eugenie was born in London. Her daughter is therefore British, automatically, from birth.

There is a catch built into the same section, and it surfaces one generation later. A child who is British by descent cannot pass citizenship on to her own children if they are born abroad. The Act allows registration instead of automatic acquisition: section 3(2) for a child with a grandparent connection to the UK, section 3(5) where the family has spent three years in the UK before the application, and the Home Secretary’s residual discretion under section 3(1). Each requires an application, a fee, and a decision. None of them is a right.

En generational cut-off has been litigated. In Romein v Advocate General for Scotland [2018] UKSC 6 the Supreme Court corrected a discriminatory gap in transmission through the maternal line. Cases like it keep arriving because families move, and the 1981 Act was drafted for a country that assumed they would not.

Portugal decided the second half of the question. Portuguese law has never applied unqualified jus soli, and the nationality reform that entered into force on 19 May 2026 tightened it further. A child born in Portugal to foreign parents now qualifies only where one parent has completed five years of lawful residence by the date of birth. Naturalisation periods went to seven years for EU and CPLP nationals and ten years for everyone else, counted from the issue of a valid permit. Eugenie and Jack Brooksbank have divided their time between the UK and Portugal since 2022. The five-year threshold had not been met.

For this family the outcome is a footnote, because the child had a British nationality waiting for her the moment she was born. In the same maternity ward, a Syrian or an Afghan mother whose own nationality law does not transmit through the female line can produce a child with no nationality at all. That is the point worth holding on to. Nationality is not one status among many, it is the status that decides which other rights a person is able to claim.

International law recognises this. The 1961 Convention on the Reduction of Statelessness obliges contracting states to grant nationality to a child born on their territory who would otherwise be stateless, and the European Court of Human Rights held in Genovese v Malta (App no 53124/09) that arbitrary denial of citizenship engages Article 8 read with Article 14. Portugal’s own reform preserves a route for children who would otherwise be left without any nationality. The gap is rarely in the drafting. It is in proof, in documentation, and in the evidential burden that falls on parents least able to discharge it.

We advise on nationality and statelessness questions arising from births abroad, on registration applications under section 3 of the 1981 Act, and on the Article 8 arguments that follow when a state refuses. We act for internationally mobile families whose nationality position intersects with other exposure, including Notificaciones Rojas de INTERPOL, extradition and removal, where a client’s nationality frequently determines which state can lawfully act at all. Where a child faces statelessness and the family cannot fund representation, we take instructions pro bono.

With thanks to Cosmopolitan UK for the original report that prompted this note.

If your child was born outside the UK and you are unsure what nationality they hold, Contáctanos en confianza.