The film tells the story of Brian Cohen, a fictional character who was supposedly born in the stable adjacent to Jesus. As Brian grows up, he becomes involved in an anti-Roman resistance group and is falsely mistaken for the Messiah.

The BBFC first classified the film in 1979, and gave it an AA certificate (no admission to persons under 14). Given the subject matter of the film, and concerns raised in a number of publications about its perceived blasphemous nature, a great many local authorities (101 in total) chose to exercise their discretionary powers and view the film for themselves.  As a result, 28 of them raised the classification to the X certificate (no admission to persons under 18) and 11 of them banned it altogether.  Interestingly, however, most of the local authorities seemed more concerned about the bad language and the nudity in a film than they were about the alleged blasphemy.  

The BBFC view at the time was that the brief moments of nudity were in a non-sexual context and of a kind to be seen not infrequently on British TV in the late evening, while the language too could be heard occasionally on British TV, and had been passed in moderation by the BBFC in many AA films through the 1970s.

On the question of blasphemy, legal opinion sought by the BBFC stated that “in our opinion the “Life of Brian” is demonstrably not about Jesus Christ or God.  It does not, in our view, offensively abuse sacred subjects or ridicule or vilify them; although it does treat, in a humorous…manner…certain biblical stories and characters.”

What was being lampooned in the film was more to do with popularised biblical history rather than the articles of faith.

Since 1979 the film has been submitted to the BBFC on a number of occasions for video and DVD classification, receiving a 15 rating for strong language and nudity between 1988 and 2007.

In February 2019, the film was submitted in a digital version for a 40th anniversary theatrical re-release. The six uses of strong language in a comic context were felt to be acceptable under current BBFC Guidelines at 12A and the film was released at that category with the Ratings Info 'Infrequent strong language, moderate sex references, nudity, comic violence'.