IF you ask William Friedkin, today's cinema just doesn't frighten the horses enough.

As the director of The Exorcist, he would say that. Given the chance to redress the balance, he has made Killer Joe, a film that would have an entire Royal Ascot's worth of gee-gees bolting.

Chosen as the opening gala at this year's Edinburgh International Film Festival, the tale of a hired gun, played by Matthew McConaughey, has generated headlines and drawn gasps for its explicit sex scenes and violence. Friedkin, frankly, couldn't resist when he was sent the screenplay by Tracy Letts, adapted from his stage play.

"I read it and thought it was brilliant – funny, disturbing, intense, all that good stuff," he laughs when we meet in Edinburgh before the premiere.

Besides McConaughey, the cast includes Emile Hirsch as a son in debt to drug dealers. It's McConaughey, though, who is the stand-out turn. The star of such drippy romcoms as Failure to Launch shows he's far more than just a handsome face and pecs.

"He's a very good actor but because he is so good looking in a Hollywood sense they don't want you to act," says Friedkin. "They just want you to show up and take off your shirt and be in a romantic comedy."

The British Board of Film Classification has given Killer Joe an 18 certificate. According to Friedkin, who won a best director Oscar for The French Connection, cinema today has become too mundane.

"There isn't enough cinema that will really involve an audience emotionally, either provoke them or get them angry at someone or something, or think about the human condition.

"That's what Killer Joe does. Most of the films made in Hollywood are simply video games and comic books, that's what it has become, an industry of that."

Audiences today want escapism, he says. It was different in the 1970s, when America was a country being torn apart by the war in Vietnam and social change.

"In the 1970s when I got started there were a lot of film-makers who wanted to and were able to provoke an audience and involve them intensely in the story.

"Like in The Godfather, for example. It wouldn't be made today. Nor would The Exorcist.

"The characters would have to have a sweater with a letter on their chest and fly around and cure evil."

Today, says this four-times married, Chicago-born son of a salesman, America is divided between the far left and the far right, leaving most people stranded in the middle. "They don't want to deal with what's going on in terms of entertainment."

Now 76, Friedkin is still as interested in politics but has become disillusioned by politicians.

"I don't believe in any politician. I don't believe what they say. They say what they need to get elected then it's often quite different. I have supported politicians. I've been virtually a lifelong Democrat. Now I'm distanced from it. I think the guy who is running against Obama is not necessarily an improvement but I think the country is already ready for a change."

Having started his career in the 1960s, Friedkin has seen nothing but change in the industry. He began in television, with one of his shows an episode of The Alfred Hitchcock Hour. It was a chance to meet the great man, not that the said legend was too impressed with Friedkin.

Brought over to meet his new young director, Hitchcock looked at Friedkin's clothes. "He said, 'Mr Friedkin I see you are not wearing a tie.' I thought he was kidding. I said, No sir I guess I forgot it on the way over here. He said, 'Usually our directors wear ties.' I started to answer and he walked away."

Friedkin remembered the encounter when five years later he won the Directors' Guild award for The French Connection. Hitchcock was in the audience.

"I gave my little acceptance speech. I had a rented tux and one of those snap on bow ties. I walked down the stairs from the stage to where he was sitting and I snapped my tie at him and said, 'How do you like the tie now, Hitch?' He just stared at me. He didn't remember at all but of course I did."

Spats over neckwear aside, Friedkin remains in awe of Hitchcock's talent. "He is basically the lexicon for film-makers. I tell people at film schools, leave school and just go watch Hitchcock's films and you'll learn how to make a film."

From The 39 Steps in 1935 to Marnie in 1964, Hitchcock's reign was long and consistently illustrious. Friedkin's career appears more of a supernova, with the early success of The French Connection (1971) and The Exorcist (1973) followed by years of edgy but ultimately under-whelming thrillers such as Cruising and Sorcerer. There was the odd flourish, as in the crime drama To Live and Die in LA. I wonder how much of a curse it was to have such success so early on.

"Not a curse at all. They're great films, I have to be honest with you. They stand the test of time so far. They are still being shown after 40 years." The Exorcist will be back next year with new prints.

McConaughey's performance might be generating talk of Oscars if Killer Joe was a less controversial piece. Friedkin has already been there and done that, and has the time in the psychiatrist's chair to show for it. Not that it was a very long time.

After winning his best director Oscar he went to see a psychiatrist on a friend's recommendation. "I felt depressed and I didn't understand why."

There was no rapport with the "dour" man sitting opposite. Friedkin felt better afterwards, though. It wasn't the psychiatry that did it; it was the simple act of talking to someone. He never went back.

"I had no reason to be depressed. It was so unexpected to win an Academy Award and for that picture. I couldn't really process it. I'm sure it was more complicated than that but I can't pinpoint it any better.

"I should have been elated and to a certain extent I was, but I think I also didn't feel deserving of it. I thought it had just fallen on my head."

What nagged him was the feeling that the process was unfair, and that one day the unfairness would be visited on him. He was right. Two years later The Exorcist was nominated for ten Oscars and won two. The Sting was the big winner that year, with seven awards.

"The Exorcist, I know, was a classic, and The Sting was like a bottle of milk. It tasted good while you were drinking it."

Killer Joe returns Friedkin to a spot in Hollywood he has made his own – the outsider grabbing the attention. Now a successful opera director as well, he doesn't need to go back behind a camera but he will.

"I feel fortunate to keep going and make the kind of films I would want to see and to make them better." He quotes Beckett: "Ever tried. Ever failed. No matter. Try again. Fail again. Fail better."

The maverick Friedkin has never been a failure; just an alternative success.

Killer Joe opens in cinemas tomorrow

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