Amazingly, many people fell for the BBC's April Fools joke back in 1957. As Wikipedia notes, spaghetti was not widely eaten in Britain at the time, so a lot of people had no idea how it was made. BBC:
[S]ome viewers failed to see the funny side of the broadcast and criticised the BBC for airing the item on what is supposed to be a serious factual programme.
Others, however, were so intrigued they wanted to find out where they could purchase their very own spaghetti bush.