Philippe Petit is reliving the walk of his life. “I am in the middle of nowhere, I am holding on to nothing, I am the play of the winds,” says the 58-year-old Frenchman, recalling the morning in August 1974 when he boldly and illegally crossed the sizeable gap between the twin towers of the World Trade Centre by shuffling across a steel cable less than 1in thick, and at a height of 1,350ft. “I am an outlaw and I should not be there,” he continues, part mythic hero, part Left Bank cliché, but all ham. “And yet I walk, and I maybe even fly!”

Petit’s breathtaking stunt, the self-described “artistic crime of the century”, is described in James Marsh’s superlative documentary Man on Wire. Here, through the testimonies of Petit’s collaborators who helped with planning and equipment, plus the canny use of archive footage and dramatic reconstructions, we are presented with a portrait of an obstinate but immensely driven man who is prepared to sacrifice everything, including friends, for his art.

Today, Petit is typically impassioned. Dressed in a black Man on Wire sweatshirt, with the quick twitchy mannerisms of an agitated bird, he is both effortlessly charismatic and faintly irascible. For a start, he’s not a wire-walker, he’s a writer, he says (he has written six books, including a treatise on wire-walking called Funambule). “I write in the sky with my body,” he says, deadpan. “I create a poem in it.”

Concerning the absence of any reference to the 9/11 attacks in the documentary, he says: “This was about glorifying the life of the tower, whereas the whole Universe knows about the death of it.”

Times Archive, 1974: Man walks on top of New York

When M Petit ended his stunt, according to one witness, 'he almost ran across the wire' into the waiting arms of the police

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And of the film itself, which climaxes with a genuinely tear-jerking account of Petit’s walk, followed by a description of his lapse into unbridled egotism, he sighs, “The ending was not like that at all. I didn’t become a diva overnight [he famously refused a £50,000 promotional deal with Burger King]. It’s not the film I would have made. It’s still beautiful, but I would have done a different film. I would have had less crying.”

Petit says that his passion for wire-walking began in childhood, when he retreated from his disciplinarian father, a pilot in the French Air Force. “I started to close myself in my own world, and to not play with other kids.” He was subsequently expelled from five schools, took impromptu lessons with the legendary wire-walker Rudolf Oman-kowsky, and began a career as a street entertainer.

I tell him that a Freudian might read his wire-walking as a metaphorical attempt to reconcile himself with his highflying father. “You know what I’m thinking now?” comes Petit’s response, a hint of genuine irritation beneath a charming smile. “F*** Freud! I have a giant disrespect for people who venture into your head and try to make sense of that which we will never solve. While they are busy trying to understand why, I’m busy doing it!”

Petit’s greatest ire, however, is reserved for the successive French governments that he decries in a vitriolic four-minute monologue which begins with his first wire-walking triumph in 1971, between the towers of Notre Dame cathedral, and ends with his disgust at France’s rejection of his art (he has done only two French walks since then). “It’s obscene that the powers that be didn’t ask this young artist, this rebellious poet of mid-air, to start creating in their own magnificent landscapes.”

And yet, towards the end of Petit’s rant, a hint of vulnerability creeps in. He speaks in sad tones of loving France, and of phoning culture ministers and asking for a chance to do something, anything, in the country.

Petit now divides his time between New York, where he is an “artist in residence” at the Cathedral of St John the Divine (he has a practice wire set up there), and a retreat in the Catskill mountains that he shares with his partner, Kathy O’Donnell.

He has, it seems, so many worlds still to conquer. He still wants to walk across the Grand Canyon and, sooner still, across Easter Island. He hopes his body will stay the course. “I run through life with things to do, and I pull my body by the sleeve,” he says. “And when my body refuses, I drag it.”

In the meantime he’s developing a blockbuster account of his twin towers wire-walk with Robert Zemeckis (who directed Forrest Gump). It’s an enormous project, he says, and will take at least three years to realise. Until then he’s given us the walk itself, through Marsh’s remarkable film, to remind us “of the miracle of beauty that talks not so much to our senses, but to our inner heart”.

Petit says this with a raffish charm, and then spins out of his chair, and out of the room. That afternoon I see him on the street. He is still wearing his Man on Wire sweatshirt. He is looking up.

Man on Wire is out on Aug 1

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