When the actress Catherine Zeta-Jones faces her alleged stalker in a Los Angeles court, it will make headlines around the world. Dawnette Knight, 33, is charged with one count of stalking and 24 counts of sending threatening letters which, according to Zeta-Jones's husband, Michael Douglas, pushed the actress close to a nervous breakdown. In one letter Knight is alleged to have written that she would slice up the Oscar-winning star like "meat on a bone" and feed her to the dogs. As Zeta-Jones may be discovering, obsession has become a side-effect of fame. The singers Mel C and Britney Spears and the director Steven Spielberg are among those who have had to take action against stalkers. Celebrity, though, is not a prerequisite for such obsession. In Britain, 900,000 adults are thought to be stalked every year; and around 20% of women and 2% of men will be stalked at some point in their lives. Stalking behaviour is often linked to domestic violence, and can in the most serious cases lead to assault, rape and murder. Now a major new study into the effects of stalking on the victims and their families is aiming to turn the spotlight on to the issue – and what can be done to help those who are targeted. Spearheaded by Dr Lorraine Sheridan, a lecturer in the University of Leicester School of Psychology and the UK's leading expert on the psychology of stalking, the study has highlighted one thing above all others: the gravity of the crime is still not being fully recognised, leaving many victims to suffer in silence. The research paints a detailed picture of what a victim goes through. It found that 14% of stalking victims suffered severe and sustained intimidation. Of the women surveyed, 43% reported being followed; 29% reported excessive, unwanted telephone calls; and 16% reported continuous spying. "Stalking is a major issue that touches millions of lives but people have so many misconceptions about it," says Sheridan. "What we want to do is to examine for the first time the far-reaching effects that stalking has, not only on its victims, but also on numerous third parties." Sheridan's research, which will be published early next year, will measure the physical, emotional and financial costs for the victim and paint a "roadmap" of the course and nature of stalking. What her research has shown above all else, says Sheridan, is that the vast majority of stalking victims are ordinary people rather than those in the media spotlight. Anyone can become a victim of a stalker and often the perpetrators are driven by very different motives. Someone who has bitter experience of how true that is is Aileen McDermott from Glasgow. Her sister, Marilyn McKenna, was threatened for three years by her ex-boyfriend, Stuart Drury, before he murdered her with a claw-hammer in September 1998. She was in the street outside her home when he attacked her. Drury, who was sentenced to life imprisonment, had started terrorising his ex-girlfriend by making malicious threats and phone calls, but the intimidation grew steadily worse. Over two years, the police were called out more than 60 times, but they were only able to issue a warning. At one point Marilyn had all the windows in her home boarded up and took her children, Brian, Laura and Ross, into one bedroom at night where they slept with a wardrobe against the door. Her eventual murder has left her wider family still traumatised. "It was heart-wrenching to watch my sister change from a bubbly, happy person into a nervous wreck," says Aileen. "To an extent we all felt we could have done more to help her and that kind of regret just eats you up. "I am sure the stress hastened the death of our mother who never truly got over what happened. We all wish we had done more to keep Drury away. At the time, however, there was a sense of disbelief. No matter how bad things became, the hope was that he would lose interest and eventually leave us alone. You get terrified to do anything in case it makes things worse, but you are not dealing with a rational person. Our whole family was in a state of terror due to this one violent man and we continue to carry the emotional scars today." Clinical psychologist Professor Vincent Egan, of Glasgow Caledonian University, says that victims of stalking can be browbeaten into a state of continual anxiety, eventually afraid to leave their homes or answer their phones. Workers at support groups see first-hand the aftermath of stalking. Mary Lockhart, of Scottish Women's Aid, says: "People wonder why those suffering violence at the hands of a partner don't just get out of the house. Often it is because they know the intimidation will continue. The person doing this will threaten to track them down and make things even worse." On the law on stalking, the campaign to make it stronger is gathering pace. In the past, someone harassing an individual could only be charged with breach of the peace and fined, but the Protection from Harassment Act 1997, as it applies to Scotland, strengthened both the civil and criminal law. Under the act, victims of harassment are able to take action in the civil courts to obtain damages for the harassment. More importantly, victims are also able to obtain a "non-harassment order" to prevent further intimidation. This order can be made if someone does something on at least two occasions, which causes the victim alarm or distress. A Scottish Executive spokesperson says: "An executive consultation in 2000 and follow-up research found that neither the victims nor those working in the criminal justice system were in favour of introducing a new offence for stalking and harassment, which can already be caught under common law and the Protection from Harassment Act 1997." Research commissioned by the executive recommended that existing practices for dealing with such cases could be improved. "The executive has been working with the police and others to take those recommendations forward," says the spokesperson. "For example, we have introduced a statutory power of arrest for breach of non-harassment orders, enabling the police to act immediately to stop any further harassment taking place. And we are working with the police and others to examine training and guidance for those who come into contact with victims of stalking and harassment." What Aileen McDermott wants is simple. She continues to speak out about what happened to her sister in the hope that increased awareness of the horror of stalking may encourage others to cease suffering in silence. "When you would ask Marilyn what she wanted to happen she just wanted it all to stop and for him to just go away," she says. "But it never did, until it was too late." Scottish Women's Aid can be contacted at www.scottishwomensaid.co.uk The National Domestic Abuse Helpline is on 0800 027 1234.