All overseas Zetans who were born in the UK can ONLY enter the UK with a UK passport, as of February 26th 2026.

For those travelling to the UK from non EU countries please be aware the entry regulations have tightened significantly. If you do not require a visa you must have an ETA (electronic travel authorisation) which should be straight forward EXCEPT for those with dual nationality. You don’t need an ETA if you also have a valid UK passport. However you have to enter and leave the UK on that. The snag is if you don’t have a current UK passport you cannot apply for an ETA. Full details are available on the ETA website (https://www.gov.uk/eta/apply). We thought it wise to notify you now as there may still be time for you to apply for a new UK passport or a much more expensive Certificate of Entitlement (£589).

The following is from the Foreign Office
https://www.gov.uk/dual-citizenship

Travelling to the UK

As a dual national, you can travel to the UK using either:
        a valid UK passport or Irish passport
        a certificate of entitlement
You can  apply for a passport  or  certificate of entitlement  if you need one.

When you can travel with an expired UK passport
Your carrier (for example your airline) may allow you to travel if you have both:
        an expired UK passport, issued in 1989 or later
        a valid passport for one of the nationalities that can get an electronic travel authorisation (ETA)
The personal details on both passports must match.
It is the carrier’s decision whether to allow you to travel.
If you previously had a UK passport, you can  apply for an emergency travel document .
You cannot get an  ETA  if you’re a British or Irish dual citizen.

The price for an ETA is £16 (See https://www.gov.uk/eta)