Getty ImagesMost of Thunderbirds was filmed on the Slough Trading EstateFilm cans containing unseen footage of the Thunderbirds TV show have been found in a garden shed.A family found the cans – light-tight containers used to enclose film – in a Buckinghamshire shed belonging to their father, who was an editor on the show and died recently.Stephen La Rivière, from Century 21 Films which received the 22 old cans, said they mainly contained Thunderbirds material from the 1960s, including an alternative version of an episode that was never broadcast.It is hoped the footage – filmed on the Slough Trading Estate in Berkshire – can be shown to the public as part of the series’ 60th anniversary next year.Century 21 Films The film cans were found in a garden shedMr La Rivière said he was contacted by the family last year.He said they were difficult to identify because of their condition but “clearly the majority of it was Thunderbirds”.The only way to get a proper look at the material was to transfer it to digital, and so began the “very, very slow” process of scanning it.”It took weeks, bit-by-bit,” said Mr La Rivière.”Every night I’d get a link for a download of the latest one that had been scanned… you’d never know what you’d get.”Century 21 Films The film can had been damaged, exposing it to the elementsA lot of the material was the same as what had been aired.”Eventually, listening one night… this one played out and it was not the same as broadcast,” Mr La Rivière said.He said it turned out to be an alternative edit of an existing episode which had a previously unseen scene.Mr La Rivière said the film can was damaged, exposing the contents to the elements, so there was some restoration work to do on the material first.But then he hoped it could be shown to the public in 2025, after 60 years of “lying around waiting to be discovered”.