Saw this film for the first time last night on Film4 and it's excellent!
The story is based in the future on a violent gang of which, the leader Alex, is imprisoned for murder. He is then chosen as the Guinea pig for a revolutionary program which makes him feel physically sick when witnessing any kind of violence or sex.
This then leads him to try and take his own life, only to fail and end up in hospital. He is then restored back to his former self through treatment.
It was a very controversial film:
Taken from wikipedia,
In the United Kingdom, the sexual violence in the film was considered extreme. Furthermore, it was claimed that the film had inspired copycat behaviour. In March 1972, a prosecutor at a trial of a 14-year-old boy accused of the manslaughter of one of his classmates referred to A Clockwork Orange, telling the judge that the case had a macabre relevance to the film.
More direct connections were made after the murder of David McManus, a homeless 60-year-old man who had 1½p stolen from him. The attacker, a boy age 16 from Bletchley, pleaded guilty after telling police that his friends had told him of the film "and the beating up of an old boy like this one"; defence counsel told the trial "the link between this crime and sensational literature, particularly A Clockwork Orange, is established beyond reasonable doubt". The press also blamed the influence of the film for a rape in which the attackers sang "Singin' in the Rain". Kubrick subsequently requested that Warner Brothers withdraw the film from UK distribution.
At the time, it was widely believed that the copycat attacks were what led Kubrick to withdraw the film from distribution in the United Kingdom. However, in a television documentary made after Kubrick's death, his widow Christiane confirmed rumours that Kubrick had withdrawn A Clockwork Orange on police advice after threats were made against Kubrick and his family (the source of the threats was not discussed). That Warner Bros. acceded to Kubrick's request to withdraw the film is an indication of the remarkable relationship Kubrick had with the studio, particularly the executive Terry Semel.
Whatever the reason for the film's withdrawal, it could not easily be seen in the United Kingdom for some 27 years. The first VHS and DVD releases followed shortly after Kubrick's death. It was also shown in many UK cinemas.