Sherlock Holmes film A Study in Scarlet from 1914 sought
Appeals for the first British feature film to depict Sherlock Holmes to be found have been renewed 100 years after it was made.
A Study in Scarlet was partially filmed in Somerset and Merseyside in 1914, but there are no known copies in existence.
The silent movie is on The British Film Institute's (BFI) most wanted list of 75 missing British films.
A spokesperson said the film was one of the "top titles" it wanted to locate to add to its archive.
A handful of titles on the list have since been recovered.
Jo Botting, from the BFI National Archive, said: "Even though some of these films have been missing for many, many years there's always a chance they might turn up.
"This film was made in 1914 so it's the centenary of it, which is partially why we're focussing on it at the moment."
A Study in Scarlet was the first British feature film to depict Sir Arthur Conan Doyle's Sherlock Holmes.
It was made by George Pearson and starred James Bragington as the famous detective.
"The film focuses on murder and intrigue amongst the Mormons in America," said Ms Botting.
"If you were in England in 1914 and wanted to film the Rocky Mountains, where else would you go but Cheddar Gorge?
"From the stills it looks like they were some very exciting scenes."
Another part of the film, depicting a wagon train crossing the desert, was filmed in Southport. Other scenes were filmed at a studio in London.
"They certainly didn't go anywhere near America," Ms Botting added.
"There are many, many British silent films we would love to find, but obviously this first Sherlock Holmes feature is one of the top titles on our list."
The BFI launched its "most wanted" campaign in 2010 to mark its 75th anniversary, in an attempt to track down some British films not held by the archive.