Oona Riley reports a former journalist leaves London today to try to prove the existence of an elusive species of ape. In an expedition backed by the Flora and Fauna Preservation Society, Debbie Martyr, aged 38, aims to bring back photographic and other evidence, including hair and faecal samples, of an ape that walks upright. Ms Martyr, former editor of a south London newspaper, has already spent two years in search of orang pendek - literally "short man". At first, Ms Martyr collated information from tales about the 4ft primate told by the local population on the jungle-clad mountain that dominates Kerinci Sadlat national park on the western side of the island, which until recently was isolated. Her journalist's nose told her she was on to something. In November, after stalking ––the ape and seeing it three times, she returned with plaster casts of the footprints of what is believed tobe a new species.

Experts were impressed. "Our scientists have reported back to us and they think there is something in this," said Dougal Muller, of FFPS. "We believe there is something there or we would not be funding this trip. If it's what we think, it could be a very significant find." Ms Martyr, whose expedition is being carried out with the help of the Indonesian government, will be accompanied by a photographer. She is in awe of the beast and the task ahead of her. "The first time I saw it I was so shocked I didn'ttake a picture," she said. "I saw something I didn't expect to see and something so totally new contrary to what I expected. here was a generally bi-pedal erect primate." Its colours correspond to those of the forest floor. "It's beige, tawny, rust red, yellow tan and dark chocolate brown.If he freezes, you can't see him." She is also aware of her responsibilities.

Orang pendek have been getting along quite nicely for millennia. Local people have known about them. They don't hunt them and they respect them because they don't have a monetary significance. "We are about to produce substantive evidence for a new great ape in one of the most important national parks in South-east Asia. We have got a job now, and I have a responsibility now as I have opened the door. "We all have a responsibility to ensure that the animal's future is not threatened as a result of its discovery. She added: "We have an opportunity with the orang pendek to put the records right. We have exploitedthe other great apes, our nearest relatives. It would be a dreadful indictment on us to see that continuing with theorang pendek." The FFPS is also keen to ensure orang pendek is left alone, safe in its own habitat. It wants to prevent a repetition of what happened in the case of the last great ape to be discovered, the mountain gorillas in Rwanda, which now have television camera crews in their territory. "If there's a new species out there - which the experts think there is - there's a much bigger question, which is how to protect and recognise the whole area," said Mr Muller.

Also included with the article: a photo of Debbie Martyr holding a plaster cast of the alleged ape's footprint, and an artist's impression (uncredited) of orang pendek. Thescale on this drawing puts the ape's height at 70-75 cm,although the article gives 4 foot.