Thousands of United Kingdom dual nationals are scrambling to secure British passports or official entitlement documents as new border rules come into force from February 25, raising fears that some could be barred from re-entering the country.

Under the revised rules, British citizens who also hold another nationality will no longer be allowed to enter the UK using a non-British passport, even if their second nationality does not require a visa. Instead, they must travel with a valid UK passport or a digital certificate of entitlement linked to their foreign passport.

The changes are part of broader immigration reforms linked to the rollout of the Electronic Travel Authorisation (ETA) system, which the government says is aimed at modernising and streamlining border controls.

Many dual nationals say they were unaware of the changes and are now facing tight deadlines, long processing times and high costs. A British passport costs about £100, while a certificate of entitlement costs £589 and can take weeks to obtain.

The new rules do not apply to Irish passport holders, but they will affect other European citizens with British nationality. Dual nationals are also not eligible to apply for an ETA and must meet the new documentation requirements instead, with airlines responsible for checking compliance before departure.

According to the 2021 census, more than 1.2 million UK residents hold dual nationality. Critics say poor communication and the short notice period have left many people at risk of being stranded abroad, particularly those already travelling or living temporarily outside the UK.

Campaign group the3million, which represents EU citizens in Britain, accused the Home Office of failing to adequately warn affected individuals. The group has urged the government to pause the changes or introduce a low-cost temporary travel authorisation for dual nationals.

The Home Office said information about the new requirements has been publicly available since October 2024 and argued that the policy brings the UK in line with countries such as the United States, Canada and Australia.

Officials said all British citizens, regardless of other nationalities, are expected to travel using valid UK documentation once the new rules are enforced.

With inputs from BBC