This is probably from the land mine dropped on the station during WW2. The story I was told was of a chap sitting on the privy, at the bottom of the garden, with the door open, watching the bombs fall over Manchester. The mine was dropped and the next thing he remembered was being in the back garden pulling his trousers back up. The draught through the sewers had blown him clean off.
Oops!
Oops, you forgot something.