A surprising rule is causing 200 Brits to be turned away at passport control every day. This little-known airport regulation has led to millions of holidaymakers being warned about the expiry date on their passports, as it could result in their holidays being abruptly cancelled.

Simon Calder, a travel correspondent for the Independent, estimates that "easily a couple of hundred people a day" are being denied boarding on their flights due to this rule. He suggests that over the course of a year, more than 100,000 people could lose their holidays because of these regulations, reports Birmingham Live.

Mr Calder has reached out to airlines, encouraging them to do more to inform passengers about this rule, especially when they are checking in and providing their advanced passenger information, often weeks before their departure date. Speaking on BBC Breakfast, he advised: "I'm afraid all you can do at this stage is try and get an emergency appointment and see if you can get a passport turned around."

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He added: "But if you're travelling later, maybe in the May bank holidays or the summer holidays then you've got time on your side and just to stress... it's only the EU that cares about the issue date, if you're going to America, Australia, Tunisia they say your passport's valid up to and including the expiry date."

Mr Calder clarifies that prospective holidaymakers are "absolutely not" covered financially if turned away at the airport, and they wouldn't receive a refund. "It's always the passengers' responsibility to make sure they are compliant."

Starting from 10 September 2018, adult passports will be valid for 10 years, beginning on the day they're issued. At the same time, passports for kids will last for 5 years, also starting on the date of issue. It costs £82.50 to renew or replace your passport online, or £93 with a paper form.

An individual must be at least 16 years old, or becoming 16 in the next three weeks, to apply for an adult passport.