Six extra seconds were cut from the film by mistake

That was "outrageous", according to the film's distributors Tartan Metro.

To complicate matters, 17 seconds ended up being cut from the film by mistake, and Tartan Metro are now racing to get the missing six seconds put back in before its release later in April.

The editing was done by an "overzealous editor", Tartan Metro said.

"He is very good at his job, he didn't realise that in film censorship, every second counts," a spokeswoman told BBC News Online.

The film company is now sending the version of the film with the six seconds put back to the BBFC so it classified in time for its release on 19 April.

But Tartan Metro are still angry that any cuts were ordered in the first place, and will put a card at the start of the film to tell people that it has been "butchered" due to "archaic" rules.

'Very upset'

The offending scene, which can be seen in France by anyone over 16, is a crucial moment that is "totally in context", according to the spokeswoman.

It was included when the film was given an award at the Cannes Film Festival 2001 by Fipresci, a federation of international critics.

The film's French director, Bertrand Bonello, said he was "very surprised and upset" at the cuts.

"The film has been sold in over 12 countries and this is the first time such a thing happens," he said.

"With the fine cast of this film, does it make all these people pornographers?"

'Extremely explicit'

The BBFC told BBC News Online the scene featured unsimulated intimate acts.

"It's extremely explicit and we would have quite happily given them a porn rating for it but we did not feel that it was appropriate in a mainstream film," a spokeswoman said.

"People would not expect to see that sort of material."

The film is about a father, a washed-up pornographic film-maker and his son who try to understand each other and build a relationship.

It stars respected actors Jean-Pierre Leaud and Dominique Blanc, who has won four of France's prestigious Cesar Awards.