Ken Russell's film, based on Aldous Huxley's 1952 documentary novel The Devils of Loudon, was first seen by the BBFC in an unfinished 'rough cut' on 27 January 1971. At around the same time, this 'rough cut' was also shown to senior executives from Warner Brothers, the film's distributor. In a rare example of a film being censored not only by the BBFC but also by its own distributor, both the BBFC and Warners expressed strong reservations about the strong religious and sexual context of the film, which seemed likely to provoke significant controversy.

Warners and the BBFC therefore drew up separate lists of the cuts they would require before the film could be distributed in the UK. In a number of cases the requirements of Warner Brothers and the BBFC coincided but a number of other cuts were unique to either Warners or the BBFC. Warners were content with the additional cuts requested by the BBFC, and vice versa, and a full list of required changes was forwarded to Russell. The cuts were intended to reduce (i) the explictness and duration of certain sexual elements, including an orgy of nuns, (ii) elements of violence and gore during an interrogation scene and the final burning of the character played by Oliver Reed, and (iii) scenes that mixed sexual activity and religion in a potentially inflamatory fashion.

A modified - but still technically unfinished - version of the film was seen again by the BBFC on 8 April 1971, incorporating many (but not all) of the cuts requested by both the BBFC and by Warners. Ken Russell had toned down or removed what had been regarded as the most difficult scenes, including the entire 'Rape of Christ' sequence in which a group of nuns cavort on a crucifix, whilst hoping that the significant reductions he had already made would perhaps allow certain other shots to remain.

The BBFC's Secretary, John Trevelyan, told Russell that the modified version was basically acceptable for an X certificate and agreed, as Russell had hoped, to waive some of the cuts Russell had declined to make. The BBFC's President, Lord Harlech, was particularly moved by the apparent sincerity of Russell's attack on religious hypocrisy and suggested that no further cuts should be required.

Nonetheless, partly in response to the strong reaction of some of the the BBFC's examiners against even the cut version, the BBFC did request further reductions in four sequences. Russell responded by complying fully with three of the cuts but insisted that the fourth additional cut could not be made properly because it would create continuity problems.

On 18 May 1971 the BBFC awarded an X certificate to the cut version of the film. Because of the scale of the changes made to the film (including the deletion of one entire scene) it is difficult to calculate accurately how much was removed from the film between January and May 1971. However, it is safe to say that several minutes were removed.

Unfortunately the opening of the film in summer 1971 coincided with John Trevelyan's departure as Secretary of the BBFC and the appointment of his successor, Stephen Murphy. Murphy was therefore left to pick up the flak for what was not really his decision. Controversy had been whipped up by Mary Whitehouse's Festival of Light campaign and there were calls for the film to be banned. A number of local authorities indeed responded to the controversy by banning the film in their areas.

In America, the film also caused widespread controversy and attracted an X rating from the US classification body, the MPAA. This X rating meant that the film would be refused an airing by many of the major cinema chains and could not be advertised in the press. Warners were therefore obliged to cut the film by another six minutes (on top of the cuts already made in the UK) in order to produce a version of the film that was acceptable for an R rating.

It was this R rated edit of the film, rather than the BBFC approved cinema version, that was released on video in the UK in the early 1980s and it was this bowdlerised version that was formally submitted to the BBFC for video classification after the introduction of the Video Recordings Act in 1984. It was classified 18 without further cuts but was a very different film to the one released in UK cinemas in 1971.

The original UK cinema version remained unavailable on video in the UK until 1997 when it was resubmitted to the BBFC following a successful airing on BBC2 in 1995. This version restored the material cut in America but did not restore the material originally cut by Warners and the BBFC. Much of the footage originally cut in 1971 was subsequently unearthed at the beginning of the 2000 and sections were shown in a TV documentary on Channel 4 in 2002. However, this material has yet to be restored to the film itself or resubmitted to the BBFC.

The film was again submitted to the BBFC in November 2011 for classification on DVD. As it was exactly the same, cut version that had been previously passed at 18 on VHS in 1997, it was again classified 18, with BBFCinsight of 'Contains strong violence and sexualised nudity'.