A mystery that has baffled film fans for nearly 40 years has been answered with Sir Michael Caine revealing how he solved The Italian Job conundrum.

In the literally cliff-hanging closing scene, Sir Michael and his fellow British criminals are trapped in a coach hanging precariously over the edge of an Alpine ravine. Each move they make towards the rear of the coach to reach their haul of stolen gold results in the vehicle inching farther over the abyss.

Charlie Croker, the gang leader played by Sir Michael, issues his famous final words: “Hang on a minute, lads. I've got a great idea. Er ... ” And then the credits roll.

Sir Michael, 75, has revealed how his gang were able to save themselves before losing their haul to the Corsican Mafia.

Now not a lot of people know this, but the producers of the 1969 movie had filmed the solution. They decided against using it, to leave audiences with the famous ending and a possible sequel.

The closing moments of the film show the gang travelling in high spirits on its way to Switzerland, having ditched the Mini Coopers that it used after a bank raid to escape through the streets and sewers of Turin. The crooks' coach careers along a winding mountain road while they celebrate in the back. The vehicle skids, with the back end left teetering over the edge and the gold slipping towards the rear doors.

Sir Michael first revealed the unscreened ending in an obscure television documentary to celebrate his 70th birthday.

He has now given further details after the Royal Society of Chemistry announced a competition last month to solve the problem. Masterminds - criminal or otherwise - are required to explain how the gang might have unloaded the gold without losing their lives.

The solution, which assumes that the coach will plunge down the mountain 30 minutes after the film's ending, must be based on rigorous scientific principles. More than 700 entries have been received.

Jon Edwards, a spokesman for the society, said: “There have been some bizarre solutions using supermagnets, donkeys and the ample-sized women who chase Benny Hill throughout the film.

“Then there are solutions with good mathematical proof and some detailed 15-page reports from engineers.”

And the film's solution - which fails to save the gold?

Sir Michael said: “In the coach, I crawl up, switch on the engine and stay there for four hours until all the petrol runs out.

“The van bounces back up so we can all get out, but then the gold goes over. There are a load of Corsican Mafia at the bottom watching the whole thing with binoculars. They grab the gold, and then the sequel is us chasing it.”

Other cliffhangers

Thelma & Louise
Do they survive driving off a cliff?

Butch Cassidy and the Sundance Kid
Do they take on an army and survive?

The Thing
Did they kill an innocent man or the alien bug?

Blowup
How does the photographer disappear in the park?

Lock, Stock and Two Smoking Barrels
Do they save the valuable shotguns or answer the mobile?

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