Originally Posted by
callum9999
It irrefutably is BA's fault. The fact that it's also the OP's fault is irrelevant to that point. If BA fulfilled their obligations then he would not be in this mess - period.
BA is behaving rationally and sensibly.
Definitely somebody at BA can take a risk, but its a big risk and opens a door for abuse. Just like a security officer turning a blind eye to an old lady carrying a pair of scissors (it was obviois she was not a terrorist - what was the risk...).
How can BA know that the person is the same person who travelled outbound?
The only evidence is an invalid (expired) ID card and some digital images plus a story. In extremis BA could review CCTV footage and do investigations but still take a risk.
The risk of accepting somebody for carriage to UK from overseas is substantially more than a £3000 fine, potentially (though unlikely) losing BA its delegated authority to bring focumented passengers to UK.
Recommend OP to get new balid documents, or it thry think they can get in, to try other airlines, drive, train...
... Easy to get human to bring docs out if they ate in uk.