The upshot of it all is that Dick, whose earlier film, Twist of Faith, about sexual abuse in the Catholic Church, was nominated for an Oscar, has come up with a wildly entertaining documentary — complete with secret video filming and car chases — that advocates greater transparency in the film-rating world.

In this country the British Board of Film Classification is an independent, non-governmental body whose members are all known to the public. Many of the examiners — who tend to be teachers, psychologists and social workers — operate on a part-time basis only. The MPAA’s Classification and Ratings Administration, on the other hand, is a secret world of full-time members who jealously guard their anonymity.

Film-makers don’t have to submit their brainchildren for classification — film rating is an ostensibly voluntary procedure — but the absence of a rating condemns the picture in the eyes of exhibitors and the mainstream media, where the distributor might want to place an advertisement.

Once a film-maker submits a film to the ratings apparatus, he or she has no choice but to accept the rating as given, or change the film.

It wasn’t censorship that really annoyed Dick, though. What got him going was the anonymity of it all. So, armed with a budget of $1 million, Dick hired a private investigator named Becky Altringer to help him track down and expose the MPAA’s examiners. For months, Dick and his crew sat outside the MPAA’s offices in Encino, California. They followed employees to lunch and even sifted through their rubbish.

Dick accepts that he has had it in for the MPAA for a long time. He finds odious the notion of a body of anonymous busybodies passing judgment on his work or that of his peers. “It’s astounding,” he says, “how many major film-makers have been caught up in it. I mean world figures, a roll-call of art film-makers of the past 40 years. And the system has hardly moved at all or even responded to criticism. I got to the point where I had to make a film and put this before the public to open up a discussion about how a better rating system could be developed.”

Dick’s big break came when Altringer, using high-powered binoculars to look into the MPAA’s security outhouse, spotted a list of phone extensions tacked to wall. A few phone calls later and she was able to piece together a list of all eight members of the ratings board.

Dick also interviewed and profiled 11 film-makers and shows footage from their censored films, along with excerpts of offending material that was cut from the theatrical release. Among them were Kimberly Peirce’s Boys Don’t Cry — the film that won Hilary Swank her first Oscar — Jamie Babbitt’s But I’m a Cheerleader, John Waters’s A Dirty Shame and Atom Egoyan’s Where The Truth Lies. Some films, such as Mary Harron’s American Psycho, were accused of being too violent, others too foul of language, such as Michael Tucker’s Gunner Palace, about US Marines in Iraq.

“Michael got an R-rating for language,” fumes Dick. “He wanted to show what it’s like out there. What are you supposed to say when someone starts shooting at you? ‘Gosh darnnit’?”

Many of the films have another element in common: homosexuality. Babbitt is not alone in wondering if the sexual content in her film was being judged more harshly because of the character’s sexual orientation.

Dick presents a compelling argument: that the MPAA is effectively limiting the revenue-generating potential of independently produced films.

Particularly relevant is the issue concerning Gunner Palace. The film’s R rating put it out of reach of young men only a year younger than some of the soldiers depicted in the film — the same kids, Tucker argues in the film, who are being recruited to go out to fight in Iraq. “His target audience was being excluded,” Dick says.

Explore Film

• Film Reviews

• DVD

• Oscars

• Bollywood

Editor's choice

• The End: the worst movie endings ever
• Introducing The Times Proms Podcast
• Heath Ledger tipped for Oscar