The BBC violated broadcasting guidelines by showing the movie Pulp Fiction 10 minutes after the watershed, media regulator Ofcom has ruled.
Tarantino's film won the 1994 Cannes Film Festival Golden Palm
Nine viewers complained after BBC Two broadcast the Quentin Tarantino movie at 2110 BST in August 2005.
Ofcom said it was screened too early because "seriously offensive language, graphic violence and drug abuse" occur in the first 20 minutes of the film.
The BBC lost three appeals against Ofcom's decision.
The Ofcom ruling acknowledged steps were taken to warn viewers and research showed that viewers were "more tolerant of adult content in films".
But it said: "Such intense material is not normally expected so soon after the watershed.
Travolta and Thurman's on-screen chemistry flourished in Pulp Fiction
"We believe the scheduling of this film at 2110 was too early, given the strong, adult content from the start."
The viewers who complained were worried that the film would encourage anti-social behaviour among young people.
The early scenes of Tarantino's acclaimed 1994 film feature an armed hold-up of a diner and the execution of a group of drug users by two gangsters, played by John Travolta and Samuel L Jackson.
The BBC had claimed that as the movie was "arguably one of the most influential and best-known films" of the previous decade, it was unlikely to offend BBC Two viewers.
The film had been screened on British television four times previously, claimed the BBC, and it had an "underlying morality" which showed the effects of violence and drug use.
"The BBC stated that there was no evidence to support the contention of some complainants that there were any links between the content and perceived social trends," added the Ofcom report.