(Reuters) - A lost Walt Disney cartoon that pre-dated Mickey Mouse has been discovered in a British film archive and will be offered for auction in Los Angeles on December 14.

Hungry Hobos was one of 26 episodes featuring Oswald the Lucky Rabbit, a character created by Disney and cartoonist Ub Iwerks in 1927 for Universal Studios.

The first production featuring Oswald, widely considered a prototype to the more famous Mickey Mouse, was rejected by the Hollywood studio, but the second, Trolley Troubles, kick-started a successful series.

Robert Dewar, commercial director of Huntley Film Archives, one of Britain's biggest independent film libraries, said he and colleagues found the only known surviving copy of Hungry Hobos during a routine cataloguing exercise earlier this year.

We've got more films than you can imagine, he told Reuters, adding that only about 40,000 of the archive's 80,000 films are fully accounted for.

We thought this one (Hungry Hobos) looked a little bit suspicious.

Amanda Huntley of the archive added: When we checked this film we couldn't quite believe our eyes. For an archive, finding a lost masterpiece is incredible -- you just don't think it will happen to you.

Dewar said the archive intended to use the money raised by the sale to help preserve its library.

Bonhams auctioneers expect the 5 minute, 21 second film to fetch $30-40,000 when it goes under the hammer.

The character of Oswald has appeared in several guises over the years, but the significance of Hungry Hobos was that it is part of the first series associated directly with Disney.

According to Dewar, adding to the film's importance was the fact that it aired on May 14, 1928, one day before the first trial screening of Mickey Mouse. It is one of several episodes of the original series still thought to be lost.

In 1928, Disney asked Universal for more money but his request was turned down, prompting his decision to part ways with the studio.

Iwerks went with him, and they developed their most famous creation, Mickey Mouse, a version of Oswald.

Oswald is a proto-Mickey, said Dewar. If you see him, you see the same shape of the head, the ears, the mannerisms.

He added that Walt Disney Co., the global entertainment company, was aware of the discovery.