Three years ago freelance archivist Richard Wiseman (below) was tasked with locating the missing rushes of Steve McQueen’s film Le Mans.

He reckoned on a one per cent chance of success.

“Everybody I spoke to about it thought that these were no longer in existence,” he says. “Even Steve’s son Chad thought that the outtakes and trims had been destroyed.”

But this “poor man’s Sherlock Holmes” kept digging and checking Porsche internet forums and doggedly tracking each trail.

He tracked down the Paris lab where the dailies were developed overnight before being returned to Le Mans each morning for McQueen’s perusal: “Apparently he would select footage for the final cut depending on the cheers or boos each piece received.”

He tracked down an unseen on-set documentary – it wasn’t shown because the film flopped – to a vault in Paris. Entitled Song of Le Mans, it includes a rare interview with original director John Sturges: “It’s clear that he wanted it to be a proper movie with racing as a background – and that McQueen wanted the opposite.”

He tracked down a three-hour home movie – some of it taken from the air – by Swiss racer Paul Blancpain.

He tracked down footage of the film’s 1969 dummy run: “They were getting their camera angles and positions right. There’s some great footage of the dice to the flag between the Ford and the Porsche.”

He tracked down the April 1970 press conference in which an underwhelmed McQueen explains that his insurers will not allow him to contest the race proper.

He tracked down McQueen’s personal documentary maker John Klawitter, whose planned hour-long promotional film was chopped to 14 minutes. He had kept the 40 minutes of overs in his garage for 40 years.

“He hadn’t looked at them since,” says Wiseman. “Luckily, because of the Californian climate, they had been preserved.”

He tracked down a black-and-white French regional TV documentary held by the Institut National de l’Audiovisuel in Paris covering the early stages of filming.

He tracked down taped interviews with McQueen, among them conversations with his holistic therapist during his fight against the cancer that eventually killed him.

He thus had the nitty and the gritty – the counterpoint to the “dreamy, poetic” rushes that he had tracked down to a Los Angeles film-editing facility.

“I’d contacted them two or three times without success,” says this ex-Autosport club reporter and former print journalist for Sky TV Guide, The Radio Times and Nuts lads’ mag. “I thought I’d try once more. This time the receptionist was different, English, which helped.

“Four days later I received an email saying that the store man had found 400-600 rolls of film, covered in dust, beneath a sound stage. It’s often the case with rare footage that someone has decided to hide it rather than let it to be erased or destroyed.

“It was an incredible moment. We were so lucky because it was one of the few buildings in the area not to have been knocked down and rebuilt, or refurbished in any way.

“It was such a thrill when the rushes were emailed to me. Because of the time difference, and because it took three hours to render them, I’d dose up on caffeine so that I could watch and log them in the middle of the night.

“Silly, really. But they were so beautifully shot, staged and lit.”

All 80 hours of them!

“The first reel nailed a myth,” says Wiseman. “It was thought that all Sturges-directed footage had been binned, burned or returned to his estate; his daughter said that she didn’t have any.

‘Suddenly, there’s a clapperboard with Sturges written on it.”

Having collected 100 hours in total – “six months works and I loved every single moment” – Wiseman now had to help director John McKenna of Noah Films synthesise them to less than two hours.

“John has a great eye for a shot, whereas I’d be picking out significant – some more than others – historical aspects,” says Wiseman. “John had the final say. His idea and role was to make the film suitable for the widest possible audience, not just diehard motorsport fans, but sometimes I’d say, ‘Oh, come on, you’ve got to use that!’”

The end result is a 102-minute gem.

For we motor sport geeks there are clips of McQueen getting to grips with a Porsche 917 on the Le Mans Bugatti circuit, and of the professional drivers lighting a strip with their road cars’ main beams so that a plane containing David Piper’s doctor can land (Piper had been grievously injured in a crash during filming).

Plus there are those elegantly and expertly shot sequences of 917 versus 512.

“We spent months in post-production adding and correctly timing the engine noises and gearchanges because the rushes didn’t come with audio,” says Wiseman.

“Some of the fast stuff is mindboggling. Really scary, they ended my dream of ever becoming a racing driver.”

For the wider audience there is a fascinating insight – not least thanks to some illuminating interviews of all the main players – into one of Hollywood’s most charismatic and complex leading men.

“The cars look fantastic and McQueen looks cool in the film, but soon you realise that there isn’t a story,” says Wiseman. “He had a vision inside his head that he couldn’t translate to the screen.

“But I was one of the four people who did Film Studies GCSE and the first thing my teacher said to me was that the misfires are more interesting than the successes.

“My hunch is that McQueen had wanted to share a 917 at Le Mans with Jackie Stewart and to make a documentary of that.

“Though there were many frustrations for him, not once – and the rushes run from June through to November – does he look the least bit bored when he’s around the cars and/or the professional drivers.

“He was a proper petrolhead.

“There was a long stretch during the 1970s when he couldn’t watch it; he was offered a sequel in 1974 but turned it down. But while he was undergoing cancer treatment he had the complete film shipped to Mexico and he showed it to the other patients.

“He had come back to it.”