Volunteers who took part in a TV ghost-hunt in one of the Capital's most haunted places claim they've been duped. Around 40 fans of the paranormal paid £100 each to take part in the filming of Chamber of Fear, set in the city's Blair Street vaults. The group, who took up the challenge after reading a newspaper advert, were locked in the vault overnight on April 29. The event organiser, Global Challenge TV, claimed the programme had been sold to a cable TV channel and participants were promised their money back if it was not screened. Volunteers say they were told the £100 was to cover administration costs and were promised a commemorative T-shirt and DVD in addition to their five minutes of fame. Craig McLaren, a joiner from Haymarket, said the programme has not been aired and promises of a refund from Global Challenge TV had not materialised. He said: "I've always been interested in the paranormal and the advert sounded really interesting so I called the number. "It was a case of killing two birds with one stone for me as it was a chance to be on TV and find out more about ghosts." Around 20 of the volunteers were from Edinburgh and the rest were from England. The two groups were kept in separate parts of the vaults and it is understood the people from south of the Border paid an extra £300 to cover transport and accommodation. Mr McLaren, 26, continued: "If I'd known that all we'd have been doing is sitting in the vaults then I would have saved a fortune and just gone on the regular tour.