Andriyko

You need to stop blaming BA for your own actions and decisions. BA does not check documents for a passenger's benefit. If BA wanted to, they could stop all document checks and just accept all the fines imposed for carrying passengers with improper documents.

BA had no need to check at LHR whether you had documents to enter the UK because you were not travelling to the UK. Depending upon which country ID you had and when it was issued, you may have had sufficient documents to enter Hungary because your expired ID may be considered to have been automatically extended by 5 years. Hungary accepts such 'expired IDs,' while the UK does not. So, when you were travelling to Hungary your docs may have been OK and BA may have had no reason to deny boarding. You had to make sure that your documents were OK both to enter Hungary and then to come back to the UK. Putting the blame on BA that they did not check that you would be able to return is just misplaced.. Had BA denied you boarding at LHR on your way to BUD even though you had proper documents for Hungary, we'd be reading about how BA is at fault for not letting you travel (and in that case BA certainly would). If, however, you did not have proper documents to enter Hungary and the gate agent did not do their job properly, you can't just ask agents at BUD to also ignore their responsibilities and let you board the plane without proper documents.