- Inside the mind of a stalker -

They are likely to be well-educated, older males with possessive or jealous personalities, and, according to the first comprehensive British study of stalkers, they will probably become violent if they have had a relationship with their victims.

DR DAVID JAMES must have a strong stomach to listen to the men whom he interviews in the course of his work. He has recently been in the company of 50 stalkers, all of whom had been arrested by the police.

These were not the kind of men (and most stalkers are male) who hung around suspiciously on street corners. Five murdered their victim, three had attempted to, four had committed grievous bodily harm and two actual bodily harm. It seems impolite to ask which cases stick in the mind, but Dr James, a forensic psychiatrist at the Royal Free and University College Medical School in North London, does furnish some details. "The cases where people have been knifed to death are pretty upsetting," he says. "Sometimes even children and pets are killed."

Dr James, together with his colleagues Dr Frank Farnham and Dr Paul Cantrell, noted that victims were much more likely to be seriously hurt if their stalker was someone with whom they had had a sexual relationship. Of stalkers in this category, 70 per cent went on to injure their target seriously. Though limited by the fact that these men all lie at the nasty end of the stalking spectrum, the findings, published last week in The Lancet, represent one of the first studies conducted into the phenomenon in Britain. And it is timely: the first proper textbook on the behaviour, penned by the world's leading stalking expert, will appear this spring. The principal author, Professor Paul Mullen, runs a clinic for stalkers and their victims in Australia. He has offered to advise doctors trying to set up a similar clinic in London.

Although stalking has been seared into the public consciousness in the wake of stories of besieged celebrities such as Zoë Ball, George Harrison, Jill Dando and, this week, Brooke Shields, psychiatrists are wading into virtually unknown territory. "The social phenomenon of stalking has come to the fore," says Dr James.

"Everybody is recognising it, coming across cases of it and wondering what to do about it. But we have no idea how common stalking is, we don't know that much about the psychopathology of people who stalk, we do not have measures by which we can assess risk. We haven't examined in any great detail the psychological damage to the victims, such as post-traumatic stress disorder, anxiety and depression. And when it comes to the treatment of stalkers, we haven't even scratched the surface."

The Dando case appears to illustrate the level of general ignorance. Newspaper reports do not suggest the television presenter had been "stalked", ie, relentlessly pursued and harassed for weeks prior to her death. Although Dr James, who has four years' experience dealing with stalkers who have broken the law, is reluctant to comment on the case, he does have a personal view: "Could it be a stalker? Absolutely nobody knows. It's a line that may need pursuit. But what would be most characteristic of stalking is someone who repeatedly tried to contact her - repeatedly telephoned or wrote - somebody who has been hanging around waiting for her over a reasonable period. I would have thought there might be more physical evidence in terms of letters, or in terms of friends, and particularly her boyfriend, having been told about her being pestered by other people. So I find it slightly doubtful, given the lack of evidence. But it's certainly a possibility."

Dr Edward Petch, a forensic psychiatrist at a secure unit in West London, hopes to set up a stalking clinic in London. He, too, is baffled by the Dando murder: "It certainly did not seem to be the sort of killing often seen in stalking cases. It looked like a professional hit. It may be that a stalker could have hired somebody, but that's conjecture."

Stalking is defined by psychiatrists as persistent, unwanted intrusions or communications that induce fear, usually taking place over several weeks. The Protection from Harassment Act introduced in 1997, which covers the issue of stalking, states that the harassment must occur on at least two occasions and be reasonably expected to cause alarm or distress.

A stalker needn't lay a finger on his victim to meet this definition; the courts will now convict for psychological GBH. Harassment can include telephone calls, e-mail, letters, notes pinned to property, unwanted gifts and more sinister missives. "There are accounts of victims being sent plastic skeletons, mutilated dolls, even vials of blood or semen," Dr Petch says. "You can imagine how terrifying it is."

Statistics from America suggest that 8 per cent of women and 2 per cent of men have been stalked at some time in their lives. There are no figures for Britain but there is no reason to think they would be substantially different. Men usually stalk women, although one in four cases involves women stalking men. There is same-sex stalking, which may or may not be homosexual. Anyone can become a victim, be they famous, ordinary, young, old, working-class, aristocrat. People in positions of seniority or responsibility - doctors, nurses, lawyers, teachers - frequently experience unwanted attention.

The stalker will most often be a former partner, but it could be a colleague, the petrol station attendant you see every week or a fellow commuter you once smiled at. They can be driven by revenge or a psychopathic compulsion. They might have delusions of love, or suffer from other delusions about their victim (George Harrison's attacker imagined the former Beatle was a witch). Sometimes the behaviour is a result of social incompetence - a man or woman who misguidedly believes that lurking in the shadows and making 20 telephone calls in an evening is a legitimate courtship. Unsurprisingly, most aggressors are thought to suffer from some kind of mental illness or disorder. Some stalkers harass their victims for weeks, others for years or even decades, and the behaviour may or may not escalate. Thankfully, serious violence is rare, with murder occurring in roughly one in 50 cases. It is perversely reassuring that, in those cases, it is occasionally the stalker who dies.

As shown by the study in The Lancet, the relationship of the victim to his or her stalker is crucial to how the stalking develops, with sexual intimacy being a relatively high-risk factor. But the lack of research means that there is no reliable way of knowing how many sexual relationships end up in harassment of a milder, but still distressing, kind.

"All we know is what we've got, and what we've got is not representative of all the stalkers that are out there," says Dr Petch. "But I suspect that there is a vast number of stalking cases we know nothing about, and most of those are likely to be ones in which an intimate relationship occurred."

How can you tell if your lover will eventually become your tormentor? It makes sense, experts agree, that people who go on to stalk may have already exhibited odd behaviour. Dr James concedes that there may be something in the idea of the "loner" stalker, and that partners who show possessiveness and jealousy during a relationship may be more likely to display antisocial behaviour when a relationship dies. Dr Petch also notes that stalkers tend to be older, better-educated and more intelligent than other groups of offenders. They are also often in jobs that do not quite tally with their educational profiles - Zoë Ball's stalker had studied physics at London University but was working as a motorcycle courier.

Media reports have created the illusion that stalking is a modern epidemic. Psychiatrists do not dismiss the idea out of hand, and are ready to muse on the reasons. Professor Mullen says: "There is an analogy with sexual abuse, which emerged dramatically in the late 1970s as a social issue. You get legislation, then come the studies and an increasing focus on the victims." Professor Mullen points out that stalking is a victim defined crime and that, as a victim, it is now easier to step forward. The illusion is reinforced, Dr James thinks, by the fact that people are becoming more frightened these days. We do not live in stable communities any more, so we do not talk to strangers and we do not let our children play in the street. We guard our privacy more fiercely than ever.

Dr James says: "If you live in a village where everyone knows you and your family, there is community pressure not to indulge in this behaviour. Relationships may also have been less easily made and rather longer-lasting when people grew up in small communities. Stalking is more likely to happen in shorter-term relationships."

The Internet has opened up another avenue by which stalkers can conduct their unpleasant business. Some websites supply names, addresses, phone numbers and even spouses' details to anyone who requests it. E-mail is voiceless and faceless. Dr James suggests that people who use chat rooms should avoid giving personal details, in the same way that they would exercise caution meeting someone from a dating agency.

Although the law affords some protection from stalkers, it does not understand them, let alone rehabilitate them. Yet the Australian experience suggests that some can reform. Those with psychoses can simply be admitted to hospital and given drugs to control their condition; those with personality disorders can be schooled in social skills, taught to manage their anger or given behavioural therapy. Professor Mullen is assessing how successful such therapies are; he thinks that at least half manage to stop stalking. A handful of stalkers have even referred themselves for treatment. Intriguingly, all psychiatrists point out that the stalker often feels distress, too.

Dr Petch is seeking support from the Home Office and the Department of Health to mirror Professor Mullen's effort: "I want to do this as soon as possible, and am talking to anybody who will listen. The primary aim is to reduce mental disorder in stalkers and victims. The latter have a desperate need for help; there is nothing for them at the moment. Gathering stalkers under one roof also allows you to try out interventions, such as group therapy."

Others wonder if a clinic is a little premature. "In order to predict which sorts of behaviour and which sorts of people are going to be the most dangerous, we need properly funded research into this, and there isn't any," says Dr James.

"Central Government, specifically the Home Office and the Department of Health, should be commissioning research into stalking, and at the moment they are not doing that."

Stalkers and their Victims, by Paul Mullen, Michele Pathe and Rosemary Purcell, will be published by Cambridge University Press in April.