BEARDED and bespectacled, Harold Shipman sits in a cell at a high security prison in the North-East, every bit the picture of the genial GP. Known as Fred to his 3,100 patients, he was renowned for his caring bedside manner, which made him popular with the middle-aged and elderly women who flocked to his surgery.

He was a doctor of the old school, a man to turn to in times of trouble, whether those troubles were medical or not, someone to trust, a human placebo who could make you feel better simply by being in his presence - but a practitioner who ended suffering by putting patients down like animals, whether they were suffering or not.

Shipman, now a life-time resident at Her Majesty's Pleasure, and currently in Frankland Prison, Durham, has carved for himself a sinister place in the annals of history.

He is unique, not simply for the proliferation of his victims, which could number more than 300, but for the respected position from which he struck.

Doctors have enjoyed the ultimate position of trust for centuries - which is why he was such a successful killer. The generation he preyed on didn't stand a chance as they, more than any other, accepted the doctor's orders without question. The fact he was able to hide his crimes for so long is an indication of the power the medical profession has to operate unchallenged.

But the motive for the mass slaughter of defenceless elderly patients may remain a mystery, going to the grave with the perpetrator himself. Shipman remains in denial and, as British law requires no motive to be proved, none emerged from his epic trial.

It even has the experts baffled. "We don't really know why he did it," says criminologist at Teesside University, Alisdair Gillespie. "He may have been playing God. As a doctor, he may have felt he had the power to save life and then realised he also had the power to kill. He may have started with good intentions, with mercy killings, but not known when to stop justifying it.

'He may also have Munchausen's syndrome by proxy, hurting people to attract attention to himself, yet at the same time covering up what he had done. Although, typically, people suffering from this eventually hold their hands up to it. It's a weird case, certainly very interesting, but frightening too. He is unique and certainly in the world class league."

Behind Shipman's pleasant exterior exists the arrogance of a professional. "He was arrogant enough to think he could kill without getting caught," says Mr Gillespie. "And we have a culture of agreeing with the doctor. People are automatically deferential with doctors, particularly the older generation, which is perhaps how he got away with it for so long."

Behind the cosy facade of his high-tech surgery in Market Street, Hyde, Greater Manchester, was an evil dispensary of death.

After a reign of 25 years, the 54-year-old was finally convicted of cold-bloodedly murdering 15 women patients.

The true number of victims may never be known. But immediately after his arrest, detectives gathered and studied files on more than 120 patients, though estimates soon put the death toll at 200 and above. The official report into the case, published yesterday, put the figure at 297 possible victims.

For the relatives of those patients, the gruesome possibility remains that their loved ones may also have been victims of Shipman's obsession with death.

The doctor's murderous career ended when he was arrested in September 1998. Two months before that, he had forged the will of one of his victims, 81-year-old Kathleen Grundy, a former Mayoress of Hyde.

But it has now emerged that six months earlier, in March, police had launched an investigation into Shipman after another local GP became concerned at the number of second signatures his practice was being asked to provide on cremation certificates for the doctor's patients.

The worries were passed on to Coroner John Pollard, who alerted Greater Manchester Police. There was a six-week investigation, headed by a detective inspector. But it was decided there was not enough evidence to inquire any further into the doctor's activities.

Shipman was to go on to claim the lives of three more elderly women, including Mrs Grundy, a tireless and lively charity worker, who died suddenly at her home in Joel Lane, Hyde, on June 24, 1998.

Shipman was called, and pronounced her dead after a cursory examination. He also confirmed that he had visited Mrs Grundy earlier that morning.

On the day Mrs Grundy died, a firm of solicitors in Hyde received a will, which purported to be hers, and was dated June 9. It left Mrs Grundy's entire estate, worth up to £350,000, and including three houses, to Shipman. The purported will left nothing to Mrs Grundy's daughter, solicitor Angela Woodruff, 53, or her two grandsons, aged 23 and 24, on whom the old woman had doted.

It was Mrs Woodruff's suspicions which finally put police on Shipman's trail.

Mrs Grundy's body was exhumed and scientific examinations found that she had died not from natural causes, as Shipman had certified, but from morphine poisoning.

Detectives came to believe with chilling certainty that they were dealing with a serial killer. A massive operation was mobilised to sift through hundreds of patients' records. Bodies were exhumed and deadly morphine found in their systems.

When the life terms were handed out, following a lengthy trial, the sentences were not simply a judgement on an evil man, but also on a profession which had allowed him to practise.

The Shipman murders rocked the foundations of an ideology set in stone for generations. More than anything else, they ended the deference experts had enjoyed and produced a new order prepared to question such professionals, one which should ensure such heinous crimes never happen again.