orbitmic

[QUOTE=fomc;30465763]
There is ZERO chance the UK immigration authorities won’t allow me in. Hence, no risk to BA of a fine. [/QUOTE]

Sorry, but if this is your starting assumption, it is a badly mistaken one, and it very much ignores the current 'mood'. I have heard of a number of cases recently that I really would not have expected. In turn, starting from that mistaken assumption makes you very unlikely to reach a solution with the airline.

The position of Hungarian emigration in terms of letting you out on an expired document also has no bearing whatsoever on what UK authorities would do. Here, the correct procedure is indeed for BA to contact UK immigration and ask for clearance, if this is not confirmed, you will need either for your home country Consulate to be more understanding and give you a laissez passer or for someone to come to bring you your passport (in theories courier companies generally do not allow for them to be mailed). You can also contact UK immigration directly and if you get some formal confirmation from them they would let you in you can certainly show that to BA or another airline.

I do agree that this is all a massive pain in the back, but you are barking at the wrong tree. It is absolutely not BA's responsibility towards you to check the validity of your credentials though it is their agreed responsibility to immigration authorities, and I any case, letting you fly without the required paperwork would not be the right recourse.