As
@Jeff Crawley has pointed out there are numerous holders of British passports that have a validity of more than 10 years because in the UK it was possible to add up to 9 months to the 10 year validity if you had your passport renewed months before it expired. You could transfer the 'unused' months from your old passport to your new passport.
Passports that are older than 10 years are not "valid travel documents" under EU law, i.e. under the law for entry of non-EU nationals into EU countries. Numerous British holidaymakers discovered this year that such was the case for them, sometimes as late as when they were already at the gate and the airport staff checked their passports. And, be aware,
they lack compassion!
As reported by a traveller who, at Cornwall Airport Newquay on Saturday, July 23, 2022, was not allowed to board with her husband and her children for a flight from England to Portugal:
"The time had come to board the plane. [My husband and my sons] were in front of me, but when a member of the ground staff checked my passport she told me it’s out of date. I replied, ‘sorry I think you are mistaken it’s valid until April 2023’. ‘No it’s not’. The ten years run from the issue date, in my case July 8, 2012.
"I was then abruptly informed that [...] I would not be able to travel. I was marched back through the busy departure gate in front of everyone while my family were still waiting to board the plane."
She also said that staff at the airport showed no compassion: "There was no being taken into a side room and told, 'we'll get your baggage for you' or 'we'll call Portugal for you and do whatever we can' - it can be a discretionary decision by the destination country.
"No discretion was made, no suggested calls were made to immigration in Portugal, no help with rearranging flights, car hire, getting home, etc, and absolutely no compassion. I would hate anyone else to go through what we have just experienced."
