Back in 1930s Britain, at the pinnacle of the comedy world were The Crazy Gang, one of whose members, "Monsewer" Eddie Gray, was known for his practical jokes.

Probably his best-known involved him shouting into the slot of a pillar box (post box) phrases such as "Well, how did you get in there?"; "Can't you open the door?"; "Not from the inside - I see..."

As a crowd gathered, he would tell the (non-existent) victim that he was going for help, and then ask the onlookers to keep on issuing reassurances hrough the slot.