More than one million Britons could be caught out by passport validity rules when travelling to Europe this summer, new research suggests.Analysis by Compare the Market, shared exclusively with the Daily Mail, found that 705,904 UK passports have fewer than three months' validity remaining, while a further 347,268 were issued more than ten years ago.Together, that means more than one million passport holders could fail to meet the entry requirements for some holiday destinations.Although many of these passports remain valid, that does not necessarily mean they can be used for travel. Many countries will refuse entry if a passport does not meet their minimum validity requirements.In the Schengen Area, which includes popular holiday destinations such as France, Greece, Italy, Portugal and Spain, non-EU travellers must have a passport that was issued within the previous ten years on the date of entry and remains valid for at least three months after their planned departure from the bloc. A whopping 705,904 UK passports currently have fewer than three months remaining before they expireTravellers with a passport issued before September 2018 should be particularly mindful of the 10-year rule. Before then, when renewing a passport the HM Passport Office could add up to nine months of unused validity from an old passport to a new one. This could mean some passports may still be in date but no longer meet the Schengen entry requirements. Overall, HM Passport Office data shows that 2.37million passports are due to expire this year. Tim Knighton, travel insurance expert at Compare the Market, said: 'Many travellers assume if they have a valid passport they can travel overseas without any issues, but that's not always the case.'He urged British travellers to check their passports and the entry requirements of the destination they intend to visit.'Some countries, including many popular European destinations, require several months' validity extending beyond the length of a trip, so it's important to check the entry requirements for each destination before travelling,' Mr Knighton added. Some 347,268 passports in circulation were issued more than ten years agoThe expert continued: 'With more than 700,000 UK passports now having less than three months' validity remaining, it's worth travellers taking a few minutes to check theirs before heading abroad. 'Renewing a passport early could help avoid unnecessary stress and reduce the risk of holiday plans being disrupted.'Plenty of British holidaymakers have had their trips disrupted by passport issues, including Victoria Vigors, who had spent two years saving for the dream two-week break to Hurghada, Egypt, with her children Riley, 15, and Roxie, nine.The 41-year-old said it would have been the family's first fortnight-long holiday abroad together and their first experience of staying at an all-inclusive resort.But after checking in online, dropping off their luggage and passing through airport security at London Gatwick without any problems, the family were stopped moments before boarding their easyJet flight.When staff scanned their boarding passes at the gate, they discovered Roxie's passport did not have the required period of validity remaining for travel to Egypt.Aside from passport validity catching holidaymakers out, stolen passports are also an issue Britons are facing. There were 422,705 UK passports reported lost or stolen in 2025. Travel insurance expert Tim Knighton has urged holidaymakers to check the entry requirements of their destination beforehandReplacing the vital travel document should be relatively straightforward, with data from HM Passport Office showing passport applications have continued to be processed relatively quickly in recent years, with a median processing time of six days in 2024 and 2025, down from eight days in 2023.Mr Knighton said: 'Travellers should do their best to keep their passport safe while away, as data shows more than 422,000 passports were reported lost or stolen last year and replacing one overseas can often be both stressful and expensive. 'While some travel insurance policies will cover lost and stolen passports, there are specific conditions and policies vary, so it's always worth comparing different deals and checking details of your cover to ensure you get the right level of protection for your circumstances.'