'Lars was trying to murder me'

In a new documentary, the maverick director Lars Von Trier gets Oedipal with his old mentor

Jorgen Leth may not be the "perfect human" (the title of his most famous film), but the 66-year-old Danish documentary maker certainly looks very pleased with himself. A handsome, weather-beaten man with a mane of silver hair, he likes his cigars and fine wines.

He also enjoys his position as honorary Danish consul in Haiti, where he has been living now for 13 years. And he is fully aware of his status as one of the senior figures in the Danish film industry. It's a measure of his confidence that no alarm bells rang when he was approached by Lars Von Trier to collaborate on the bizarre documentary, The Five Obstructions.

The challenge Von Trier set him was to remake - in five different ways - The Perfect Human (1967), a 12-minute short in which we see an androgynous actor in a dinner jacket prancing in front of the camera as a Desmond Morris-like narrator tells us all sorts of strange facts about him.

In theory, Von Trier and Leth are old friends. At regular intervals in the film - which is co-financed by Yeslam bin Laden, Osama's estranged brother - we see them meeting up at the Zentropa Studios in Copenhagen to enjoy some vodka and caviar and to discuss how the documentary should proceed. Their conversations seem friendly enough, but it's hard not to see the challenges Von Trier sets Leth as evidence of some deep-rooted Oedipal animosity. "Yes, he does have this father-son thing with me," Leth muses. "Maybe you could analyse it more deeply and say he's trying to commit a father- murder in the long run. He was doing it with a mixture of love and an ambition to break my self-assurance down."

The duo go back a long way. In the early 1970s, Von Trier used to be an underling at the Danish Film Institute in Copenhagen at a time when Leth was one of the senior consultants. It seems the younger man hasn't fully forgiven his old mentor for failing to recognise the young genius in his midst. "He was a young student working in the corridors, doing small jobs," Leth recalls. Von Trier used to sneak off and watch films in an old editing suite. One title he ran at least 20 times was Leth's The Perfect Human. "Later he reproached me for not remembering him. He told me that he was this little boy who adored me... that was the first meeting between us. It was significant, of course, because he always keeps everything in his mind."

A few months later, Von Trier and Leth ran into each other again. Von Trier was a student at the National Film School in Copenhagen. Leth was a senior tutor. By then, Leth's fellow teachers had recognised that Von Trier was a special talent. "But he was also regarded as a very strange man," Leth notes.

Leth's wife at the time, an actress, disliked Von Trier intensely. "There was a sadistic strain to him," Leth recalls. "He was demanding impossible things from recognised Danish actors who were much older than he was. That was already there in his student films."

Von Trier and Leth were not especially close, but the older man knew that the young director admired his work. In particular, Von Trier relished the way Leth had always set himself formal constraints before starting on a project. In the mid-1990s, when Von Trier drew up his film-making manifesto, The Vow Of Chastity, and launched Dogme, he acknowledged Leth as one of the key influences on the movement.

Not that Leth was remotely clubbable. While he admits he enjoyed the recognition from young Danish film-makers, he wasn't interested in signing up to Vow himself. Nor was he supportive of the "dogumentary rules" Von Trier announced last year. ("I am not a brother in any brotherhood. I am not into collective film-making," he says tartly.) Nonetheless, when Von Trier invited him to dinner when Zentropa was launching its documentary arm and asked him to collaborate on a film, Leth quickly agreed. The title, The Five Obstructions, comes from football. In the early 1990s, Leth made a documentary about the Danish footballer, Michael Laudrup. When dogged defenders tried to obstruct him illegally, Laudrup always shrugged them off. In the film, Leth does the same to the studs-up, hard-tackling Von Trier.

The "victim" in The Five Obstructions is Leth, but the film turns out to be infinitely more revealing about Von Trier. At one stage, the director states that the "greatest gift" an actor can give him is to "screw up".

Leth's first assignment was to go to Cuba and remake The Perfect Human "with no edit more than 12 frames long". Leth took advantage of the restrictions, shooting 1,000 scenes which he edited down into seven elegant, if staccato, minutes of footage. Von Trier liked it, but felt thwarted. He had failed to trip his mentor up.

In the second episode, Von Trier tells Leth to go to "the most miserable place on earth". So he heads to Bombay's red-light district and stages a one-man dinner party. "I knew I was sitting in the midst of lost souls and human misery, but I was giving my performance... it's possible I could have had a breakdown, but that would have been an adequate solution also."

As the project proceeds, Von Trier grows ever more desperate, and by the time they get to the fifth obstruction itself, he is so frustrated he tells Leth: "You will do nothing at all!", and directs the film himself. "It was really touching for me to see that film," sighs Leth. "He was doing a personal striptease."

The fifth obstruction is Von Trier's admission that he has failed to persuade Leth to let his guard down and risk making a bad - but honest - movie. "I simply can't. I can't. I don't think I can. My instinct will always be to find an interesting and satisfying creative solution to his attempts to deconstruct me."

There is now talk of Leth making a documentary about Von Trier's forthcoming staging of Wagner's Ring cycle at the Bayreuth Festival. If this goes ahead, it will be Von Trier who suffers: Leth will be able to enjoy one of his fat cigars as his would-be tormentor from The Five Obstructions faces his most daunting challenge yet.

'The Five Obstructions' will be shown on 7 November at the ICA, London SW1