GETTING to the nub of Frank Searle is as demanding a task as proving or disproving the verity of the monster he longed to photograph. Searle, detested by many, remembered fondly by others, was in equal measure a showman, a raconteur, a hermit and a charlatan. He produced 20 pictures of “the beast” of Loch Ness which, most now believe, were created using fence posts, logs, tarpaulins and old socks. Nonetheless, he was committed to the loch — no doubt to the borders of obsession — and claimed to have put in 20,000 hours of patient Nessie- spotting in order to get his pictures. Perhaps those fruitless hours drove him, finally, to create the monster himself. He certainly enjoyed the dappled fame that followed.

Searle set himself up at one of the loch’s lonelier reaches, at Lower Foyers, until 1985. The police had questioned him about the petrol-bombing of Adrian and Maralyn Shine’s Rosetta Project camp at Achnahannet. Searle fled, and neither his friends nor enemies saw or heard from him again. It was rumoured that he was seeking lost gold in the Hebrides, or in Cornwall, or had died in some misadventure. A filmmaker, Andrew Tullis, sought him out for a documentary called The Man Who Captured Nessie, to be shown on Channel 4 this year. His investigations led him to the seaside town of Fleetwood in Lancashire. It transpired that Searle had lived inconspicuously there for 18 years, and had died in his bedsit just a few weeks earlier.

Eric Frank Searle was born in Staines, Middlesex, in 1921. Little else is certain except that he joined the Army and may have become a paratrooper (he claimed to have tricked his way into the Armed Forces at 14 and to have gone on to fight with the SAS). Certainly he came back from service in Palestine with the bottom part of his left leg missing — lost, he said, on an anti-terrorist mission. He settled down to life as a greengrocer until 1969, when a spate of literature on the mysteries of Loch Ness inspired him to abandon his home comforts in London. He spent the next 15 years in tents and caravans.

St Columba is believed to have been the first to spy a creature in the loch in 565. But the legend began in earnest in 1933 when a couple reported seeing an animal “rolling and plunging” on the surface. The next year the first hoaxer, Robert Wilson, fooled the multitude with a picture of a plastic monster mounted on a toy submarine. Of the many hoaxers that followed, Searle was the most shameless.

Only the most ungenerous doubt that he set out with the best intentions of getting genuine pictures of a creature he truly believed in, But he had little equipment and his approach was unscientific. With a couple of cameras and two tiny boats, Seeker and Seeker II, he patiently scanned the horizon. There was no substitute, he said, for diligently watching and waiting. In fact, there were plenty of alternatives, deployed exhaustively by scientific expeditions, but Searle could not afford them. Besides, he seemed as determined to cultivate a reputation for wry eccentricity as he was to document the monster.

His first recorded “sighting”, in July 1972, was near Balachladoich Farm. His photograph showed what appeared to be a two-humped creature to the credulous — and a floating log to anyone else. The picture was published to great acclaim in the Daily Mail, and for the next two years Searle’s solitude was broken by eager monster-spotters. Experts were willing to entertain the idea that it could be a plesiosaur, although others pointed out that 14 of them would be required to maintain a breeding herd. This just encouraged visitors to reinvent the Great Glen as a valley of dinosaurs.

Searle established the Frank Searle Loch Ness Investigation in a unit beside his blue caravan — supported entirely by visitor donations — and erected signposts to it, while embellishing his displays with new pictures. He had ample charm. “I first met Searle in 1976,” recalls Tony Harmsworth of discoverlochness.com. “I thought his material was real back then, because Searle was completely honest for at least 95 per cent of the time, and he had a real twinkle in his eye.”

When Harmsworth set up his own, more commercially-minded exhibition in the 1980s, Searle saw it as an act of trespass. “I wanted to show Searle’s pictures, explaining their provenance,” he recalls. “Searle was outraged at the idea, and I found a note on my windscreen saying ‘You’re a dead man’. Yet Searle’s exhibition was in a place with hardly any visitors. He seemed uninterested in making money. We were not really in competition.”

Searle’s succession of photographs — about 20 in five years — suggested that the shyest of cryptozoological beasts was becoming almost exhibitionist. Searle attributed them to his sniper training in the Army, saying it had given him the patience to wait in silence and lightning-fast reactions whenever the quarry appeared. One picture showed an unusually detailed head or tail rising from an indistinct froth of water. It was soon identified as a section of brontosaurus cut out from a mass-produced dinosaur postcard and re-photographed against a loch background. Searle further injured his credibility by snapping what he claimed were flying saucers.

In 1975 the broadcaster Nicholas Witchell published The Loch Ness Story, an unmitigating rejection of Searle’s findings which dissected each one of his photographs. Searle replied with Nessie: Seven Years in Search of the Monster the next year, but the book was slated for cribbing other people’s research.

Searle was unmoved by his growing reputation as a crank. He stayed where he was, and loved meeting the tourists who made the trip to his lonely end of the loch. He took on a succession of Girl Fridays, mostly foreigners, whom he seemed effortlessly to enchant with his wit and self-belief. Lieve Peten, a multilingual Belgian, stayed longest, becoming his “assistant huntress” and visitor liaison. Another of his assistants, according to Harmsworth, complained that the only monster that she had encountered along Glenurquhart was Searle himself.

Peten fondly recalls her days with Searle on her website (which also details UFO sightings in Belgium), living frugally and relying on nothing but loch salmon, when in season, for food. She defends Searle’s photographs, stating: “He has taken a number of pictures, but none that he ever claimed to have any real scientific value.”

Searle was reviled by other Loch Ness researchers. He seemed quite unaware, or unconcerned, that he was affecting “genuine” research. He had a long-running dispute with Adrian Shine, a Fellow of the Royal Geographic Society who, in securing funding and support, had continually to debunk Searle’s photographs. While Searle’s and Harmsworth’s vistor centres fought for the hearts and minds of tourists, Searle attacked “gift-shop commercialism” and Shine’s sonar explorations through his regular newsletter. Fed up with Searle’s unkind words, Shine looked into libel action against Searle’s publisher.

The dispute peaked when the words “Shine con-man” appeared, sprayed in red across the ancient stone of Urquhart Castle, just before the petrol-bomb incident which precipitated Searle’s disappearance. Practically nothing is known of his life after that. Just before his death he had rejected the idea of moving into sheltered accommodation. He never married or had children.

Searle’s photographs are still on show, without qualification, at another exhibition which cheekily calls itself the Original Loch Ness Visitor Centre. His pictures still win believers, and they still infuriate his detractors. Yet it is the loch’s mystery, rather than its scientific facts, that fuel Scottish tourism — and nobody did more than Searle to draw the visitors there.

Frank Searle, self-styled cryptozoologist, was born on March 18, 1921. He died on March 26, 2005, aged 84.