There was a mixed response to the BBC's April Fool joke on Panorama in 1957. Some people were fooled, some found it funny, but some were angry that a serious programme would air something so frivolous.
The hoax documentary showed a family from Ticino in Switzerland carrying out their annual spaghetti harvest, with
women carefully plucking strands of spaghetti from a tree and laying them in the sun to dry.
It may seem odd that anyone could be fooled by this, but spaghetti was comparatively rare in 1950s Britain, with food rationing only ending in 1954. Also, it is thought to have been the first televised April Fool prank, so it was unexpected.
Original B&W photo.
The Panorama segment.