NOBODY took any notice of two girls heading towards Cottingley Beck one summer afternoon in 1917.

Armed with a camera, a few hatpins and some hand-drawn pictures of dancing fairies, the pair set about staging a prank. Their aim was to play a trick on family members who had teased them for “playing with fairies” at the beck.

What resulted was to change their lives forever. And more than 60 years after the Cottingley Fairies hoax fooled the world, it had a devastating effect on the man who came to expose it.

This year is the centenary of the fake photographs, taken by cousins Frances Griffiths, nine, and Elsie Wright, 16, at Cottingley. Five images, taken in 1917 and 1920, fooled scientists and intellectuals, including Sherlock Holmes author Sir Arthur Conan Doyle. One of the 20th Century's most sensational hoaxes, the Cottingley Fairies are regarded as charming folklore - but, like many fairytales, a darkness lies beneath.

In 1981 Frances, then an elderly woman, finally admitted the fakes. It caused a media storm - and for Bradford University lecturer Professor Joe Cooper, who devoted years of research to the case, it led to a nervous breakdown and the collapse of his marriage.

Joe, who died in 2011, was an astrologer and psychic investigator who lectured in sociology at Bradford College and University and taught at Margaret McMillan Teacher Training College.He wrote books on the paranormal and carried out one of the first studies into a scientific basis for astrology. Also a gifted musician and composer, he founded the Yorkshire Ukulele Circle.

He reported his Cottingley findings in The Unexplained magazine in 1982 and later wrote a book, The Case of the Cottingley Fairies, leading him to being an advisor on 1997 film Fairy Tale: A True Story, inspired by the hoax.

It was a chance meeting in a book sale queue that led him to Frances and Elsie. “It was February, 1975. We got talking to a lady from Cottingley, it was a cold day, we’d taken hot soup and I offered her some,” says Joe’s former wife, Shirley, 80. “She said she knew the ladies who took the famous photographs and she put Joe in contact with them.

“He became obsessed with the Cottingley Fairies and spent years visiting those two old ladies. They weren’t speaking to each other by then so he had to meet them separately, he was constantly up and down the motorway going to see them. Then he went missing for nine months. I contacted Frances who said, ‘I haven’t seen him since I told him they were fakes’.”

Despite several accusations of fakery over the years, the cousins insisted their photographs were real. Joe believed so too. Learning it was all a hoax made him ill. “He became a changed man after meeting those two,” says Shirley. “They watched him devote years of his life to all that research, going back and forth to them both. I think it was a power thing with them. I met Elsie once and she couldn’t look me in the eye. She spent the whole time playing with a budgerigar and a table-tennis ball.”

Adds Shirley: “Joe was an eccentric man. He planned our children’s births under ‘compatible’ signs of the zodiac. He was drawn to unusual things; I accepted his interest in the paranormal, but I just couldn’t bring myself to say I believed in fairies. I couldn’t support that and he ended up blaming me for them not being true.

“Sixty-five years after those photographs were taken, they ended my marriage. When I heard about plans for a statue of Elsie and Frances I thought: ‘Please, no’. I don’t want them glorified.”

The first hoax photo, in 1917, was of Frances surrounded by Elsie's hand-drawn fairies. They took two photographs that summer, developed in Elsie’s father’s makeshift darkroom, and the pictures remained in the family until 1920, when Elsie’s mother took them to a meeting of Bradford Theosophical Society. They reached the attention of Conan Doyle, whose fascination with spiritualism and the supernatural was well known. Intrigued by the fairies, he gave Elsie and Frances an expensive camera, to take more photographs. Using a hatpin, the girls stuck a paper fairy holding a harebell onto a leaf and another cut-out, a leaping fairy, was pinned to a willow tree branch.

The fifth picture- a spooky image of transparent fairies peering from a misty nest - is different to the others. Conan Doyle called it the ‘Fairy Bower’. When the hoax was revealed, Frances insisted this was the only image that was real, and that she had taken it. But Elsie claimed she'd taken it and, like the others, it was a fake.

“Dad always believed in the Fairy Bower, I think it gave him hope,” says his daughter, Jane Cooper, of Ilkley. "He was a good man. I didn’t believe in fairies as a child but I didn’t want to hurt his feelings. Mum was the practical one; while Dad was researching fairies she’d be getting my brother and I ready for school.

“It was Dad who brought back into focus a story which had laid dormant for 65 years; Elsie and Frances spoke to him about it for the first time since the early 1920s. He often took film crews to Cottingley and led tours of the beck. I remember an American coming over to try and disprove the images, he took photos of me at the beck with my Sindy dolls in the trees.

“When Dad went on TV’s The Big Breakfast as “the world’s leading expert in fairies” I feared they’d make a fool of him but he simply said, ‘It’s not whether you believe in fairies, it’s whether they believe in you’. He was contacted by many people claiming to have seen fairies.”

Jane believes her father’s near-death experiences as a bomber command navigator in the Second World War influenced his ideas. “He was 19, he was shot at nightly and believed something was looking after him. It wasn’t unusual for airmen to have a talisman," she says. "Dad suffered post-traumatic stress and cultivated a larger-than-life personality to deal with that.

"His father, my grandfather, had been in the First World War and his job was to piece together the limbs of dead soldiers. Dad grew up in a strict household, with bleak accounts of his father's experiences.

"Dad was a scientific man but he believed in the supernatural. He loved nothing more than taking on the sceptics.”

Jane has been working with the National Media Museum on acknowledging her father’s contribution to the Cottingley Fairies story in its schools programme. She is also writing a script about the hoax, which she plans to develop into a play or musical.

“People think the Cottingley Fairies is this lovely tale of two little girls, but it had a massive impact on our lives,” says Jane. “I want the world to know that my father was a good man.”