Louis Malle's drama about child prostitution in early twentieth century New Orleans had already aroused controversy in the press and overseas when it was first seen by the BBFC on 28 March 1978.  However, it raised particular difficulties for the Board given that it was submitted at the precise moment the Protection of Children Bill was making its way through Parliament.  This Bill, which became the Protection of Children Act 1978, would criminalise the manufacture and distribution of any 'indecent' images of children under the age of 16.  Given that the film featured not only a child prostitution theme, but also full frontal nudity involving a 12-year-old Brooke Shields, it was inevitable that the Board would have to scrutinise the film very carefully.

Examiners noted that "the film shed a gentler and more sympathetic light on its child-whore subject than Taxi Driver did, and raised similar issues [...] The period setting also gives a historically truthful context that softens the impact.  Given that we have passed Taxi Driver, I think we should pass this, though, in the current climate, Scorsese's film would probably now cause us more qualms than it did in its time".  Following on from this initial examiner screening, the film was seen again by the Board's Secretary, James Ferman, on 29 March, and then by the Board's President, Lord Harlech, on 5 April, accompanied by representatives from the Home Office and the Office of the Director of Public Prosecutions. 

After this, James Ferman wrote to the film's distributor on 28 April, explaining the difficulties: "As you know, your film Pretty Baby is likely to run into some difficulties in Britain if and when the Protection of Children Bill is enacted into law.  The Bill passed through the Commons last week and is expected to have a fairly easy passage in the Lords, in which case it should receive the Royal Assent some time during July [...] There is no doubt that this Bill will apply to any film which purports to show children under the age of consent engaged in scenes which may be found to be indecent".  Ferman went on to comment on the screening that had taken place with Home Office officials and representatives of the DPP: "All those present admired the film, and the senior representative of the DPP gave it as his opinion that should the film be reported to their office, he personally would not recommend prosecution.  On the other hand, one of his colleagues stated that, were it given to him as a barrister to handle the prosecution of the film, he would be able to make a strong case against it.  The representative from the Home Office gave it as his opinion that the sponsors of the Bill would not want to amend it so as to leave such a film free of prosecution, since this was precisely the sort of subject they might be seeking to control".  Ferman concluded that: "There is no knowing, at this stage, how this Bill would work out in practice.  Nonetheless, assuming that it does become law this summer, there will most certainly be a testing time during the year following its passage when only the verdicts of a number of test cases will demonstrate where British juries are prepared to draw the line on indecency as regards children.  As this is a film of some considerable merit, I would not like to see it involved in a controversy of this kind.  Furthermore, the BBFC would also be placed in a difficult position if forced to rule on the film during the first year of this new law, and for that reason I have to say unequivocally that we would like you to withdraw the film for the rest of 1978 and not to submit it without further discussion with us next year".

In the meantime, the film was seen again at the beginning of June 1978 by members of the BBFC, as well as by members of the DPP's office, Customs and Excise, and the Williams Committee, who were currently looking into the whole issue of film censorship and obscenity.  Details of these screenings were leaked to the press, resulting in the BBFC issuing a public statement on 2 June 1978 stating: "No hasty decision will be taken by the British Board of Film Censors on the film Pretty Baby, which was seen by some members of the Board yesterday.  The Protection of Children Bill currently going through Parliament raises new legal issues, and since it is not the role of the Board to pre-empt the wishes of Parliament in such matters, we shall be waiting until the Bill has been passed in its final form by both Houses before making our decision on the film's acceptability in Britain". 

Following the passing of the Protection of Children Act into law in July 1978, and taking into account the views of the various people who had seen and considered the film, the Board concluded that two minor cuts would be required before the film could be granted an X certificate.  Accordingly, a cuts list was sent to the film's distributor on 16 August 1978.  The cuts were as follows:-

• (1) Reel 4 - In the scene in the bathroom, delete moment where Madame pulls away towel which Violet is holding in front of her for modesty, and cut straight to close-ups of Violet and man looking at each other
• (2) Reel 5 - Delete full-length nude shot of Violet posing for Bellocq on the sofa.

These proposed cuts were put to the film's director, Louis Malle, who was very reluctant to make any changes to his film.  Although he agreed to make the first cut, in the bathroom scene in reel 4, he was particularly reluctant to delete the shot showing Violet lying on the sofa.  For him, this was one of the key shots in the film and a direct reference to the publication, 'Storyville Portraits', whose cover image had inspired the whole project. 

Accordingly, in October 1978, he met with James Ferman in person to discuss the matter.  Following on from that meeting, James Ferman sent a letter to Louis Malle on 10 November 1978.  He stated: "Since our meeting, I have had a chance to discuss the position further with my colleagues, and I put to them your very strong feelings about the scene in which Violet is posing nude on the sofa.  We all appreciate the visual beauty of the shot and the significance it has for you in its evocation of Bellocq's photographic style.  Yet we can see no way round the objection that the model in this case is only 12-years-old and that she has been posed in a manner which many adults would feel to be indecent for a child of that age.  I mentioned the very important point that you wished to demonstrate the degree to which an obsessive artist like Bellocq could inadvertently exploit a child like Violet purely for the sake of his work, but I was reminded by my colleagues that, ironically, this charge of inadvertent exploitation could also be levied at a director making a film on the subject with a child actress".

Given Ferman's clear position that the BBFC could not accept this shot as filmed, Louis Malle initially suggested that it might be possible to find an alternative shot in which less detail was visible.  However, when his search for alternative takes proved fruitless, he agreed to darken the existing shot so that no detail in the lower half of the girl's body would be clearly visible, most specifically any genital detail.  Ultimately, this solution proved acceptable to the Board and the film was finally classified X on 27 July 1979.  In total, six seconds had been cut from the bathroom scene, in which Violet is displayed naked to a client, and the scene in which Violet lies naked on the sofa had been optically darkened.  Following on from this, in November 1979, James Ferman was able to report to the film's distributor that:

"You will be relieved to hear that the Attorney-General was able to announce in the House of Commons last week that the Director of Public Prosecutions is not to take any action against your film Pretty Baby". 

As was BBFC practice at the time, the BBFC also issued an explanation of its classification decision in one of its regular bulletins to local councils.  In respect of the optical darkening of the sofa scene, Ferman commented: "Such a compromise has seemed absurd to some commentators, and it may well be that a British jury would have supported them in failing to find the original pose indecent in British law".  Nonetheless, in spite of the Board's ambiguous feelings about the necessity of the cuts, the film was banned by Cardiff City Council.

Subsequent to the film's run in UK cinemas, at least outside Cardiff, the film was released on VHS in 1981.  At the time, there was no requirement for videos to be vetted or classified by the BBFC and, perhaps inadvertently, the film's distributor released the uncut version of the film.  Significantly, no legal action was taken against the uncut video release under the terms of the Protection of Children Act.  Following the introduction of the Video Recordings Act in 1984, which made it a legal requirement that all films released on video in the UK should be classified by the BBFC, it became necessary for the BBFC to consider all the VHS tapes that were already on the market.  Because of the scale of the task, a staggered implementation of the Act was introduced, under which Pretty Baby would need to be assessed and classified by 1988. 

Accordingly, the BBFC was presented with a VHS cassette of the released version of Pretty Baby in June 1987.  Noting that the version released was uncut, examiners referred the film to the Board's Director, James Ferman.  Examiners conceded that, given that legal cuts had been required in 1979, it might be necessary for the same cuts to be implemented for video classification, in which case all existing copies of the film would have to be withdrawn from circulation and destroyed.  However, examiners also expressed scepticism about whether the cuts were really necessary, suggesting they might have been an overly cautious response to the new legislation.  At least one examiner even floated the idea of passing the video 15 uncut, given its visual discretion.  James Ferman sympathised with the suggestion that the original cuts should now be waived and showed the video to the Board's President and Vice Presidents.  Ultimately it was concluded that "All admire the film and support waiving the original film cuts".  Accordingly, Pretty Baby was classified 18 uncut for video release, with the previous cinema cuts waived, on 4 September 1987.  Although this permitted the existing VHS copies to remain on the shelves, no fresh release of Pretty Baby took place on VHS and the film became increasingly difficult to find, other than for occasional TV screenings. 

In 2006, the film was resubmitted to the BBFC, in a widescreen version for DVD release, the first time it had been issued on a home viewing format since the original VHS tapes were released in 1981.  On this occasion, the film was classified 18 uncut with the BBFCinsight 'Contains child prostitution theme.  Serious consideration was given to whether the film's visual discretion might warrant a downwards reclassification to 15.  However, given the difficulty of the film's theme and the complex manner of the theme's presentation, it was concluded that the existing 18 was still reasonable and defensible.