The only known surviving copy of a Charlie Chaplin film which features some of the earliest known animation is set to go on sale.
Antique collector Morace Park bought the film reel on online auction site eBay for just £3.20 because he liked the look of the tin.
But the film inside, called Charlie Chaplin in Zepped, started him off on a worldwide journey as he tried to discover more about it.
The footage, expected to fetch a six-figure sum, shows Chaplin bringing down a German Zeppelin aircraft and is believed to have been made as a morale-boosting propaganda film for British troops.
It contains animation and what might be an early form of special effects.
Mr Park, who has travelled to the US, Switzerland and Germany to investigate the origins of the forgotten film, said experts differed in their interpretation.
He said some believed it was Chaplin’s experimental film, while others said it was made without his knowledge.
There is even a debate over whether the aircraft is real or some kind of puppet.
Mr Park said: “This film is an enigma. It leaves so many unanswered questions. When we showed it to people their draws just dropped.
“But even though we’ve shown it to so many people around the world they can’t agree.” He said he wanted to bring attention to the importance of forgotten films, adding: “Something like this has never come to market before so how do you value it?”
Mr Park, 47, from Henham in Essex, bought the film in September 2009, discovering the extremely fragile 35mm nitrate reel inside a battered tin box.
The footage lasts almost seven minutes and shows scenes of a Zeppelin raid over London.
Paul Wells, professor and director of the animation academy research group at Loughborough University, believes “the Zeppelin is possibly real, but could also be a premature form of puppetry”.
If the image of the Zeppelin is genuine, it would be the only known live footage of the aircraft over London at that time.
On the other hand, if it is a puppet animation, it is an extremely early example.
The film was classified by the British Board of Film Classification in 1917 and may have been sent to Egypt on a morale-boosting mission for troops.
Film critic and Chaplin biographer David Robinson said: “Though the opening title boldly announces Charlie Chaplin in Zepped it is highly unlikely that its star ever knew of the film’s existence. Certainly Chaplin had no hand in its making.
“Yet this film has its own special interest as one of the earliest known compilations of found footage.
“The anonymous maker has put together out-takes from three earlier Chaplin films (His New Profession, made for the Keystone Company in 1914, and A Jitney Elopement and The Tramp, both made for Essanay in 1915) with sequences of stop-motion animation, and actual shots of dirigibles (airships).
“In addition the film uses a technique of painting or scratching directly on the film to produce the effect of bomb explosions behind Charlie’s figure.”
Stephanie Connell, head of entertainment memorabilia at Bonhams said: “The fact that this fragile and flammable nitrate film has survived from 1916, features the most iconic film star of the period and has never previously been seen by the wider public, is incredible and it will no doubt become a significant contribution to the history of early film.”
The film will go on sale at the Bonhams Entertainment Memorabilia auction in Knightsbridge on Wednesday, June 29.