evidence: UK travellers used to be able to carry up to nine months left on an old passport over to a new one. This meant that a passport could be valid for more than 10 years. But the rules changed after Brexit, and the majority of EU countries no longer accept British passports that were issued more than 10 years before the date of travel. This is known as the "10-year rule". [...] - be valid for at least three months after the day you plan to leave (the "date of expiry")