Passport validity rules for travellers from the UK to destinations worldwide are easily found from official sources, in particular the UK Foreign Office's travel advice.
Yet airlines continue to disrupt vacation plans by falsely claiming that a passenger's passport is not valid for travel.
British Airways is the latest. BA ground staff at London Gatwick turned away a Scottish passenger who was fully documented for a two-week holiday in Florida.
The airline has since apologized, saying: "This was a human error by one of our colleagues and we are reaching out to our customer to apologize and make it right."
BA staff's mistaken decision to deny boarding to passengers follows numerous cases of travellers to the European Union being wrongly turned away. For months, easyJet and Ryanair have enforced rules of their own devising to turn away passengers with valid passports. Both airlines are now in compliance with EU regulations.
But why does an airline refuse to let a passenger board who has followed the red tape for his destination? And what can you do if this happens to you?
These are the most important questions and answers.
What was the last problem?
On September 20, 2024, 62-year-old Kathleen Matheson was denied boarding by British Airways ground staff at Gatwick Airport to board her flight to Orlando, Florida. She was on a two-week trip and was carrying a British passport that was valid for travel to the US (and many other countries) until November.
But BA staff claimed the US requires six months' validity on passports. They insisted Ms Matheson would need a new passport to board a transatlantic flight.
Mrs Matheson and her husband Allan, 56, showed proof from the Foreign Office website that her passport was valid. Ground staff ignored the evidence.
She then called the British Airways helpline, where the agent agreed with her interpretation of the US rules but said they could not override the ground staff at Gatwick.
BA has since apologized for the extraordinary course of events.
The unjustified denial of boarding cost the couple thousands of pounds in lost bookings and extra expenses, which they now hope to reclaim from British Airways - in addition to statutory compensation.
They travelled to Orlando on a Virgin Atlantic flight two days later, having lost 48 hours of their two-week holiday because of BA's decision. Mrs Matheson said she was "devastated and exhausted by what has happened".
Read more: EasyJet missed six chances to admit it wrongly turned away a passengerAren't passport problems usually Brexit-related?
Yes. After the UK voted to leave the European Union and the government negotiated that British travellers would be 'third country nationals', two conditions came into effect:
If The Independent verified at the time, these rules are independent of each other. So a traveler whose passport was issued on January 1, 2015 and is valid until July 1, 2025, can enter the European Union (or wider Schengen area) on December 31, 2024 and stay for up to 90 days.
Incomprehensibly, easyJet, Ryanair and other travel companies - as well as the UK government and some media - have confused these two conditions by falsely claiming that "passports expire after 10 years".
Read more: Air Passenger Compensation: What Are Your Rights If a Flight Goes Wrong?Europe's largest budget airlines introduced a fictitious rule that no British passport could be accepted for travel to the EU for more than nine years and nine months after the date of issue. They wrongly refused to let thousands of passengers board, later having to compensate them, before finally complying with the real rules.
Why would airlines be so keen to turn away passengers?
Airlines can be fined thousands of pounds if they let someone board a plane without the correct paperwork for their destination. The standard US Customs and Border Protection fine for an airline "carrying an alien into the United States who does not have a valid passport" is $5,851 (£4,384) per passenger.
In addition, the airline must fly the passenger back as soon as possible. If the next flight is full, a booked passenger may have to be dropped off to make room for the deportee.
Ground staff at international airports face a huge challenge in ensuring passengers are properly documented. They must interpret regulations for a multitude of destinations for travelers holding passports issued by one of nearly 200 countries.
Read more: 'You get off the plane': British Airways under fire after breaking key rule by turning away overbooked passengersTheir assessment takes place in a high-pressure environment, while time is running out until the flight's departure time.
It is not surprising that staff sometimes err on the side of caution. In an uncertain situation, they may decide to turn passengers away rather than risk their bosses costing the airline thousands of pounds.
To err is human, and given the complexity of the process, it is understandable that mistakes are occasionally made.
Read more: I have a dual passport, but which one should I use?Yes - even before Brexit, leading UK airlines occasionally wrongly turned away passengers with valid British passports travelling to continental Europe.
But it is incomprehensible that BA, which flies thousands of British citizens to the US every day, has staff checking documents who are unaware of the most basic rule: that America has no minimum validity period for a British passport.
Anyone whose passport was issued on April 1, 2014 and is valid until January 1, 2025, will be allowed to fly to the US on New Year's Eve 2024.
What happens if I am wrongly denied boarding?
Read more: Why Those Airport Boarding Times Matter - Even If Your Flight Is DelayedAlways be polite. First study the rules as stated here for Europe and here for many other countries to make sure you are properly documented. If you are sure of your status, invite the ground staff to take a look for themselves.
Specifically for the US, this document from Customs & Border Protection makes it clear that British citizens "only need to hold a passport valid for the period of their intended stay".
If these approaches don't work, ask a supervisor or manager for a verdict. You can even, like Ms. Matheson, call the airline's customer service.
Still no progress? Politely ask the ground staff to put in writing why you were denied boarding. Some travelers have found that this concentrates the minds of the airline staff, who then reverse their original decision.
Despite everything I was rejected...
The best way to save your trip - and to demonstrate that you have been treated unfairly - is to find another seat on another airline, ideally on the same day from the same departure port, that is willing to take you.
Read more: Have I found the worst public transport connection from the airport?You may find the cost of a ticket to be extremely high. Assuming you are right, you can then claim back the additional costs you incur as a direct result of the airline's decision to deny you boarding.
Will I receive compensation and reimbursement for the money I lost?
If you are denied boarding a flight leaving the UK or European Union against your will, despite having the correct documentation, you are entitled to £220 for a journey of 1,500km or less, £520 for a journey of more than 3,500km and £350 for everything in between.
In addition, the airline must reimburse you for any costs you directly incurred as a result of not allowing you to travel.
If you have lost a package holiday due to an unjustified refusal to board, the legal responsibility to refund you lies with the tour operator - who will likely recover the costs from the airline. But that is not your problem.