The Pythons' satire on organised religion in general and Christianity in particular (and not, as most people seemed to think at the time, on Christ himself) is one of cinema's comedy classics.
The plot is simple: Brian Cohen (Graham Chapman) is mistaken for the Messiah from his birth and, as he grows into adulthood, the Messiah tag, with typical Python humour rather than saintly humility, sticks. Along the way, he gets involved with a crackpot Judean liberation movement led by John Cleese and finally finds himself a victim of Roman justice, courtesy of a lisping Michael Palin.
The film was to have been funded by EMI Films until chief executive Bernard Delfont read part of the script and it was left to ex-Beatle George Harrison, a friend of Eric Idle, to put up the money to make the film. Even while they working on it, there were rumbles of the trouble ahead. "The British Film Censor's office was being inundated with messages," says Terry Jones.
In the event the BBFC gave it an AA certificate, meaning that anyone over 14 could see it. As James Ferman (head of the British Board of Film Classification at the time) said: "We took the view that 14-year-olds are quite capable of telling the difference between a lampoon and a serious attack on people's religious beliefs."
Unfortunately, not too many teenagers run local councils, so in some of the more benighted parts of Britain, the film was banned. And, in America, they went further. The Catholic Conference's Office for Film and Broadcasting gave it a C certificate: Catholics seeing it were automatically damned.
Fortunately, sanity prevailed and the film was a hit on both sides of the Atlantic, giving rise to many a mimicked catchphrase and scene, not least the classic "He's not the Messiah. He's a very naughty boy!"