An anime historian had the cartoon for 70 years before he realised it was one of seven lost films.

The two-minute short features Oswald the Lucky Rabbit, a precursor to Mickey Mouse.

Yasushi Watanabe, 84, bought the film from a toy wholesaler in Osaka when he was a teenager, paying only ¥500 (£3.45 at current exchange rates).

Originally called Neck & Neck, the 16mm cartoon was tagged with the name Mickey Manga Spide (Mickey Cartoon Speedy), and remained in Mr Watanabe's personal collection for 70 years.

The significance of the film only became apparent when he read the book, Oswald the Lucky Rabbit: The Search for the Lost Disney Cartoons, written by long-term Disney animator David Bossert and published last year.

"As I've been a Disney fan for many years, I'm happy that I was able to play a role," he told the Asahi Shimbun newspaper, which confirmed with the Walt Disney Archive that the cartoon was one of a handful of lost Oswald films.

Another missing Oswald film, Sleigh Bells, was found in the BFI archives in 2015

Walt Disney and Ub Iwerks created Oswald the Lucky Rabbit in 1927, and it was Disney Studios' first character to have its own series.

A total of 27 cartoons were made, but the anthropomorphic rabbit became the centre an intellectual property dispute, with Universal Studios wrestling the rights to the character in 1928.

In response, Disney began work on a new lead character: one that would eventually be known as Mickey Mouse. As for Oswald, it was left in animation purgatory until Disney CEO Bob Iger bought back the rights in 2006.

"What's particularly good about this story is that it shows the spread of these films across the globe," Jez Stewart, the BFI's animation curator told the BBC.

"How the films propagated across the world and where they end up is almost as interesting as the film itself."

In 2015, another lost animation featuring Oswald was found in the BFI's archives.

Stewart says these discoveries are important, but only part of the picture when it comes to early animation. At the same time as Oswald was being made in the US, for example, Bonzo the dog was having surreal adventures on UK screens.

"I think it's a shame that it sometimes takes a lost film to be found to draw attention to the films that are there."