Simon Calder has warned more than one million Brits they face being refused entry to the UK if they don’t take action following a change to passport rules.

The travel expert says there are 1.2 million people who now face being told “prove you are British or you can’t come in”. These are people who have dual nationality, meaning they are citizens of both the UK and another country. Until February 25, 2026, these people could use their foreign passport to entre and leave the UK.

But that option has now ended and British citizens who want to enter the UK from abroad must now use a UK passport or an expensive “certificate showing right of abode”.

The UK Government explains: “All British citizens have the right of abode in the UK (meaning, the entitlement to live or work in the UK without any immigration restrictions). This makes them exempt from immigration control. They don’t need an immigration officer’s permission to enter the UK but, to be granted entry based on their British citizenship, they must be able to demonstrate that they have the right of abode.

“They are expected to do this by showing a current British passport or a certificate of entitlement to the right of abode (an official document). The most obvious choice for most people is to apply for a British passport. Applying for a certificate of entitlement may take longer, and costs more (£589) than applying for British passport. People can’t have a certificate of entitlement at the same time as a British passport.”

Most of the 1.2 million Brits who live abroad live in European Union member states and states in the wider Schengen area, as well as Australia, Canada, Japan, New Zealand, Singapore, South Korea and the USA. And passports issued by these countries allow travellers to visit the UK for a stay of up to six months for tourism, family visits or business. But British dual nationals cannot now use those foreign passports to enter and leave the UK.

Home Office minister Lord Hanson said it “is part of plans to modernise and digitise the UK’s border and immigration system by providing a much clearer picture of who intends to travel to the UK for short periods … strengthening security and ensuring a smoother travel experience”.

The Home Office added: “People with dual citizenship for the UK and one of those [non-visa] countries can no longer simply use their foreign passport to travel to the UK. Many British dual nationals are affected by this. For example, Australia, New Zealand, Canada and all EU Member States are non-visa national countries. British-Irish dual nationals are not affected. An Irish passport can still be used for unrestricted travel to the UK.”