Talking of Heathrow, the VOLMET (not the ATIS) was recorded by a guy in an office at the old north side radar unit (roughly where Compass Centre now stands)
Hot summer night so windows open; one of our guys just going home at 3 am after a 'first half'; accidentally beeps his horn as he gets into his car.
Office window flies wide open and a torrent of abuse is hurled at him; the bloke was just doing the next VOLMET and the car horn 'beep' went on the tape!!
I daren't tell you about the 'unwanted' voice recorded on the Glasow ATIS one night as I'd get banned from the forum.