IT was one of the greatest hoaxes of the 20th century and it even fooled the creator of Sherlock Holmes.

Now photographs of the Cottingley Fairies, which fooled Sir Arthur Conan Doyle, are going up for auction and are expected to fetch more than £2,000.

The two pictures were taken in July and September 1917 by 16-year-old Elsie Wright and her nine-year-old cousin Frances Griffiths, in the village of Cottingley, near Bingley in Yorkshire.

The two girls, like so many children then and now, believed in fairies and set out to prove their existence, little knowing that their practical joke would stir such controversy and fool such eminent figures as Conan Doyle, who lived in Minstead in the New Forest.

Borrowing Elsie's father's Midg quarter-plate camera, and with the use of coloured paper cut-outs and hat pins they staged their scenes near the stream at the end of Elsie's garden.

They first showed Frances with four dancing fairies and two months later photographed Elsie seated with a one-foot tall dancing gnome.

While Elsie's father, a keen amateur photographer who developed the prints, never doubted they were fakes, his wife Polly was a believer and in 1919 she took prints of the two photographs to show members of the Theosophical Society in Bradford where they were giving a lecture on fairy life.

From there things spiralled out of control, first through the enthusiastic belief of leading society member Edward Gardner, who used photography expert Harold Snelling to produce photographic prints of them to be sold at Gardner's theosophical lectures in 1920.

It was during 1920 that Conan Doyle, a committed and leading spiritualist believer, became aware of the photographs and wanted to use them for an article on fairies he had been commissioned to write for The Strand Magazine.

Gardner and Doyle sought further expert opinions from the photographic companies, while Gardner met the Wright family and organised a camera and plates for the girls to try and capture more photographs of the fairies.

During the summer of 1920 the youngsters managed to "capture" three more images of themselves with fairies.

Following the publication of Conan Doyle's article a great public controversy raged with leading scientists and writers voicing their opinions in support of and against the truthfulness of the photographs.

The story has rumbled on intermittently ever since, and is considered one of the most bizarre and successful photographic hoaxes of the last century.

The photographs will go under the hammer at Dominic Winter Auctioneers in Cirencester, Gloucestershire on October 4.

Auctioneer and photography specialist Chris Albury said: "These photographs are surprisingly rare and much sought after.

"These two photographs are from 1917, but were likely printed for sale in 1920, to be sold at theosophical lectures advocating a belief in spiritualism.

"While there was a lot of scepticism in the authenticity of the photographs at the time, the story never went away and Elsie and Frances only confessed that the photographs had been faked in 1983, Frances even then maintaining the fifth photograph was genuine and that she believed in fairies.

"I imagine these photographs were printed and sold in fairly modest numbers and as the story faded from public interest most would have been thrown out as junk, so survivals are few and far between.

"There will be interest from all sorts of collectors interested in fairies, spiritualism, Conan Doyle and photography hoaxes, so competition will be fierce."