Experts believe they have found the first ever fiction film made in the UK.
The 50-second film is a drama of the arrest of a pickpocket
The film, dating back to 1895, was found in a stash of films which had lain untouched for 60 years in an attic in Redditch, Worcestershire.
The 50-second film, Arrest of a Pickpocket, is believed to be the precursor of the modern day British film industry.
The experts at Sheffield University's film archive have restored the film for a public screening due in October.
The film shows a pickpocket being chased by a policeman before being wrestled to the ground, aided by a sailor, and arrested.
The drama was produced by pioneering film maker Birt Acres and can be dated by newspaper billboards, from 14 and 15 April 1895, used in the background.
Experts at National Fairground Archive at the University of Sheffield believe it was made a week after the billboards.
That would make it the oldest British film in existence, pre-dating the previous oldest UK film, Acres' footage of the 1895 Derby, by nearly two months.
The film was found at the home of 79-year-old Frank Williams.
It was originally owned by his grandfather George who showed films as part of his travelling circus.
It was only when Frank Williams' niece Sue Bristow handed the collection of films to Sheffield University last year that its significance was discovered.
Experts predict that in another three months chemicals in the film would have destroyed the footage.
Dr Vanessa Toulmin, director of the National Fairground Archive, said: "This is the first ever British film that was filmed as a story, of people telling a story in film. It's the founder of the British film industry."
The film has now been restored and is due to be screened at the Pordenone Silent Film Festival in Italy in October.
Sue Bristow, said: "The family are thrilled. It's a wonderful discovery to know that these films are being preserved for posterity and that future generations will be able to watch them."