Forces around the country have been issued with new guidelines urging them to clamp down on a crime which is escalating so quickly that the number of cases is rapidly approaching one million a year.
The rise of so called "text stalking" - often committed by vengeful former boyfriends - is causing particular alarm, with victims hit by threatening words or pictures dozens of times in a single day.
Last week, a shop worker at the Harvey Nichols store in Knightsbridge, London, was gunned down by a man who had been following her for months. It emerged that 22-year-old Clare Bernal had been bombarded with text messages before she was killed by Michael Pech, her ex-boyfriend turned stalker.
Results of a worldwide study expected in a few months' time will show that 900,000 British people are harassed or receive unwanted attention each year, and that the widespread use of mobile phones is a major factor. Based on research carried out by the University of Leicester, this is the first global analysis of the phenomenon.
The courts, too, are concerned about offenders using new "weapons", including mobile phones and computers, to wage campaigns of harassment. As a result, judges are ensuring that they word restraining orders carefully so that convicted stalkers cannot evade the law by using new technology which is invented after any ban has been imposed on them.
In May this year, a 49-year-old school janitor was convicted of sending threatening messages to his lover's mobile phone. William Smith, a married father of three from Lanarkshire, admitting harassing the woman by sending messages to her phone.
Hamish Brown, a former detective inspector with the Metropolitan police who wrote a guide on dealing with stalkers, said another disturbing development was vengeful boyfriends using mobiles to send compromising pictures of their partners.
There are no statistics showing the scale of phone stalking - and the dividing line between unwanted attention and harassment is unclear. Experts, however, are certain it is on the increase. Last year Nadine Coyle, a singer with the group Girls Aloud, complained of being stalked by mobile. But it is not just celebrities who suffer. Magazine editor Faith Brotherston, 30, from Hednesford in Staffordshire was persecuted for a year after getting a text by mistake. "It started out innocently. I got a text that said something like 'car won't start, not going to make it to club, can you arrange a lift for Mark?'. I texted back saying they had the wrong number and added something like I hoped they had a good night," she explained.
Then she got another text saying "Thanks Wrong Digit, you sound nice, what are you doing tonight?" and after that she got 15 messages a day, most of them inconsequential. "Then the floodgates opened. At one time I was getting up to 40 texts a day and they became more sinister," she said. "He began to detail sexual fantasies and dreams. He bombarded me with texts in the middle of the night.
"I decided I couldn't ignore it any more and went to see a friend in the police. He advised me to tell my tormentor I'd been to the police, so I did. When he said I couldn't spoil his fun that easily, I changed my phone and have been very cautious ever since."
The frightening truth, according to Dr Lorraine Sheridan, a senior lecturer in forensic psychology at the University of Leicester, is that "virtually anyone can become a stalker, and virtually anyone can become a victim".
In 2003, there were 5,640 prosecutions under the harassment legislation introduced in 1997 to deal with stalkers. About half of these cases resulted in a conviction.
The majority of victims know their stalker. Half, like Pech, are ex-lovers. The sheer range of stalkers defies stereotypes but psychologists like to try to categorise them, and ex-partners are category number one. "These people are not usually mentally ill in the conventional sense," says Dr Sheridan. "It is about power and control. These are the people who are very jealous in the relationship. They need to control their partner and if their partner leaves then they just go mad."
Research from Italy suggests that 20 per cent of victims become suicidal. One in three suffers from post-traumatic stress disorder, a similar percentage to victims of domestic violence. Before it happens to them, people see stalking as a bit of a joke but their worldview is shattered by the reality. They come to believe that nothing can protect them. And sometimes, as in Clare Bernal's case, they are right.
Additional reporting by Linda JonesReuse content