Last updated at 00:00am on 19th January 2008 A new film tells the gruesome story of the Demon Barber of Fleet Street, who turned his clients into meat pies. Ghoulish fiction? Recently found evidence suggests otherwise ... On a late March afternoon, the London drizzle and fog made it seem as if night had already fallen. A lone figure paused outside a church in Fleet Street, pulling a gold-braided hat over his eyes and wrapping his expensive cloak around him. Something caught his attention - the flash of metal in the candlelight of a filthy shop. Its window was dirt-encrusted, but through the grime a notice could be made out: "Easy Shaving For A Penny". The stranger ran his hand over his stubbly chin. It was 1785 and he had arrived in London early to do business and was to stay overnight. Perhaps he should smarten himself up. The proceeds of the business deal were folded in his wallet; who knew what the evening would bring? Minutes later, the man settled in the barber's chair, but not for long. At the throw of an unseen lever, the seat tipped backwards and the floorboards in front of his feet rose up, the ceiling spinning. He was flipped out of the chair and into the cellar below. If his neck was not broken by the fall onto the basement's stone floor, Sweeney Todd, the barber, would soon slit his throat with a razor. Then the man was stripped of his money, and his flesh. Along with 160 others, his body was sliced up and used in pies. It is a bloodthirsty tale which touches one of mankind's most primal fears: that of being killed and eaten. But this forerunner of Hannibal Lecter, and a serial killer far surpassing the Yorkshire Ripper, also has a morbid attraction. Sweeney Todd's name is seen in Victorian 'penny dreadful' newspapers and then 19thcentury melodrama, complete with his own catchphrase, "See how I polish 'em off!" In modern times, the Demon Barber's tale has been adapted first as a Stephen Sondheim musical and now a Tim Burton film starring Johnny Depp and Helena Bonham Carter. Todd's story, however, has always been dismissed as exactly that - a story. For years, his existence was denied. Academics pronounced him a fictional composite, his grisly character an amalgam of several serial killers. From my early days as a journalist on Fleet Street, I, too, have been fascinated by Todd. But over 25 years' research, I discovered new information that proves inescapably that Sweeney Todd existed. I pored over archives in London and Washington, looked at 18th-century maps and scrutinised contemporary publications. They revealed that Todd's life and crimes were more intriguing, more curious and more gruesome than previously suspected. Moreover, his background conforms to the psychological profiles of serial killers built up by modern police criminologists. The Demon Barber's crimes, it turns out, are no urban myth. Sweeney Todd was born on October 26, 1756, in Brick Lane. The house in which the child first breathed the fetid air of the East London slums is not known, but it was probably near Spitalfields. His troubled, violent early life mirrors that of more recent killers. Todd's mother, not 20, scratched a living winding silk. Her husband, a struggling silk weaver, was a drunk who beat his son and his wife. Todd said later: "My mother used to make quite a pet of me. I was fondled and kissed and called a pretty boy. I used to wish I was strong enough to throttle her. What the devil did she bring me into this world for, unless she had plenty of money to give me so that I might enjoy myself in it?" This undercurrent of malevolence was compounded by the young Todd's bizarre interest in the instruments of torture displayed at the nearby Tower of London. To escape his parents' brawling, he lingered in the Tower's museum, where thumbscrews, racks and other macabre tools were displayed to discourage citizens from dissent. Todd hated his home life and his ginsodden parents. He is unlikely to have shed a tear when, in the freezing winter of 1768, they disappeared, possibly dying on the streets while seeking booze. Equally mysterious is how the boy survived that winter, turning up the next year as an apprentice cutler. His master, John Crook of Holborn, specialised in razors. The boy's life abruptly changed again in 1770, when Todd was jailed for five years for petty theft. His crime is not recorded, but he entered Newgate prison aged 14 feeling ever more bitter. In prison, fate overtook the semiliterate boy. The prison's barber, a grizzled old man called Plummer, employed him as an assistant, where he soaped condemned men's chins for shaving before they walked to the gallows. Despite his association with Plummer, Todd did not escape the vindictiveness of fellow prisoners. On one occasion he was left for dead after a beating - for pilfering from a murderer. The Sweeney Todd who walked out of Newgate in autumn 1775 was a strapping 19-year-old with a grudge. The years had made him morose and resentful and he would soon repay London for the violence it had visited upon him, many times over. With his new skills, Todd made a good living as a street corner barber. Within five years of leaving prison, he had earned enough to open a shop near Hyde Park Corner. There the barber was helped by a young woman, whom he referred to as his wife despite his never marrying, and who bore the brunt of Todd's growing rages. Already, the signs were there in the barber's behaviour. Criminal psychologists now believe violence in the home is an early indicator of a propensity towards murder. They rehearse brutality behind closed doors before embarking on murderous careers. By now, violence was the norm for Todd, as victim and perpetrator. The event that pushed him over the edge occurred in December 1784. A yearly news chronicle of the time tells the story. "A young gentleman, by chance coming into the barber's shop to be shaved and dressed, and being in liquor, mentioned having seen a fine girl in Hamilton Street, from whom he had had certain favours the night before. The barber, concluding this to be his wife, and in the height of his frenzy, cut the young gentleman's throat from ear to ear and absconded."