At the end of each episode of The Kingdom, his horror-cum-hospital satire that aired on Danish television in the mid-Nineties, Lars von Trier appeared as himself, with a message for the viewers. Dressed in a bow tie and with the slimy demeanour of a circus impresario, he would say things such as "We have begun gently, so not to leave anyone behind, but things become more hectic in the next episode" or "I'm very happy with part two: I'd call it poetic and captivating". If the audience found his programme predictable, von Trier suggested, "Then look at your own life. Is it monotonous and depressing? Yes? Then enjoy the comfort of the familiar".
These appearances remind one of Hitchcock's arch hosting of the Alfred Hitchcock Presents TV series in the Fifties and Sixties. Hitch was often no more than front man for those programmes, but the effect is the same: the manipulator confronting his victims face-to-face, the Punch and Judy man determined to take a bow as himself, the joker in the playground declaring "Hey, it's me. Got you".
At first glance the director of Breaking the Waves and The Idiots may seem to have nothing in common with Hitchcock. But the impish chap signing off The Kingdom does share certain distinct qualities with the late master: technical virtuosity; a bitter-tasting treatment of female characters; and this perverse delight in confounding and challenging the audience.
Ask von Trier if he is a manipulator and he immediately answers, "Oh yes. Oh yes. But you know, I feel that I'm always playing with open cards. Whenever I've used a certain technique to play with the audience, it was fairly evident. I think you can manipulate with the audience, or you can manipulate them without their acceptance. I would like to do it with their acceptance."
In that sense, the mercurial Dane's films always announce themselves ahead of time: the declaration of the Dogme manifesto, which famously threw out the technical backbone of conventional filmmaking, paved the way for The Idiots; Dancer in the Dark was hyped as a groundbreaking musical as well as a damning critique of America, a country he had never visited a fact which enraged the US critics and immediately included everyone else in the "joke".
And now we have Dogville: the film without a set or props; the film which dares to put Kidman in chains; and the first part of a trilogy, USA: Land of Opportunities, the idea of which has again had Americans at the Cannes Film Festival, where the movie premiered, foaming at the mouth.
So von Trier's cards are indeed on the table. Or are they? Once upon a time he would been dragged to Cannes screaming, his fear of flying making travelling something of an ordeal. When I met him this time, in the exclusive and serene Hotel du Cap, he seemed positively chipper with the effect that he is even harder to trust.
Despite its nominal Rocky Mountain setting, the whole of Dogville takes place on a bare stage, the houses of the town marked out in chalk on a black floor. There is even a chalk dog. This imaginary town is the backdrop for a parable about the perniciousness of community and the morality of revenge, with Kidman as both victim and executioner.
The inspirations that von Trier cites are certainly theatrical: Brecht, particularly Pirate Jenny's song from The Threepenny Opera ("And they asked me which heads should fall, and the harbour fell quiet as I answered All"); and the sprawling, hugely ambitious RSC production of Nicholas Nickleby in the 1970s.
"I'm not a great theatre-goer, but the simplicity of theatre is something I'm longing for in film," he says. "Especially since computers came in and you can do Lord of the Rings with a million characters, it is such a good feeling to go back to something very simple. I wanted the audience to forget that there are no houses or whatever. This makes you invent the town for yourself but, more importantly, it makes you zoom in on the people."
So what of suggestions that this is no more than filmed theatre? "I think it is really dangerous to divide things into film or theatre or literature, because it all comes from the same thing, it's make-believe, telling a story; these definitions of what film is limit everybody."
What's true is that Dogville takes the Dogme philosophy one step further, paring away the embellishments of cinema until the audience has no choice as in the theatre but to concentrate on the characters. The staging of Festen, the Dogme film by Thomas Vinterberg, at the Almeida Theatre next month, is entirely logical, while Dogville itself could be lifted straight from the screen to the stage. But, argues von Trier, "this does not make it anti-cinema. I just want to free some inspiration. I'm sure there are a lot of things we can do with this media that, right now, are not being done at all."
As usual, his working methods created numerous demands on the actors. An estimable cast that includes Lauren Bacall, Ben Gazzara and Paul Bettany had to occupy the stage with nowhere to hide pretty much constantly during six weeks of shooting, whether they were in front of the camera or not. And that was just the half of it.
Stellan Skarsgard, the Swedish actor who has appeared in most of von Trier's films, recalls the director's tricks with wry humour. "If you don't trust Lars then you shouldn't work with him, because it can be very painful," he says. "I had a scene where I was blackmailing and raping Nicole. And after four or five takes he suddenly says to me: 'Stellan, couldn't you try to play it as a romantic comedy?' So then I played it as a romantic comedy. Of course the scene doesn't work like that. But there are a few exchanges, a few seconds which suddenly becoming very interesting, because the angle of attack is different. So we did a really bad scene and that gave us a couple of seconds of gold."
Apparently even the game Kidman was a little perturbed when she saw the chains von Trier had waiting for her. Her character is the latest in a long line of humiliated women in the von Trier oeuvre, but the director waves aside intimations of misogyny. "I would say that these characters are not so much females as they are a part of me. It's very interesting to work with women, I can relate to them. I know that some people think that I don't like women, but obviously that's not true. It's men I have problems with," he adds, slyly.
He is equally unrepentant about situating his story in America. "I do feel very critical of what is happening there. I've criticised some politics in Denmark too, but no-one gives a shit about politics in Denmark, because they don't have power. The problem with America is that they do have power. And if you have the power you have to be merciful that's what I learned when I was a child; and when you have the power, you have to think."
Although von Trier is about to start shooting the second part of the trilogy, Manderlay (without Kidman, who had to back out because of a hectic schedule), what we're really waiting for is his production of Wagner's great opera cycle The Ring at Bayreuth in 2006.
"It's difficult, because I've never done anything like it and I don't know anything about opera. I'm a complete idiot. But I'm working hard," he says. Here again is that naughty glint in his eyes. "I'm so happy about it. And we have agreed that I'm not going to make anything that will provoke anybody." Yeah, right.
'Dogville' (15) is out on 13 February