This year the National Union of Students is for the first time circulating a letter to its officers on campuses throughout Britain asking them to inform students against cults and to collect information about cult activity. The letter describes recruiting strategies students must guard against and the dangers of particular types of cult manipulation.
"We are sending out basic common-sense stuff such as 'don't give out telephone numbers and addresses to people you don't know'. It's not just freshers who are at risk. We are told that mature students are also being heavily targeted," says Julie Eason, NUS vice-president (welfare).
Students are prime targets - one group has described halls of residence as an "evangelistic paradise". Intelligent, often idealistic, students tend to be open to spiritual searching. Many are away from home for the first time, slightly disorientated - lonely even - and glad of the friendly face and personally flattering conversations that are the mark of cult members on recruitment drives.
A warm introduction, an invitation for coffee or to a party accompanied by an effusive welcome called "love bombing", a more insistent invitation to join a bible study group, or attend a course and before long the unsuspecting can be hooked; sucked into what can be a totalitarian, litist society that controls their lives, isolates them from other friends and family, and drains them of their time and money.
According to the Cult Information Centre (CIC), a charity set up in 1987 to educate people about the way cults operate, there are more than 500 such groups in the UK which fall into two main categories: religious cults - whose vision of the world is black and white, those on the outside damned to eternity and those on the inside being the chosen "saved" and therapy groups, which work through offering so-called self-improvement and self-help techniques and courses.
The CIC defines a cult as having five key characteristics: it uses psychological coercion to recruit and indoctrinate potential members; it forms an litist totalitarian society; its founder leader is usually self-appointed, dogmatic, messianic, charismatic and unaccountable; the cult believes the end justifies the means to solicit funds or to recruit; its wealth does not benefit its members or society.
Ian Howarth, general secretary of the CIC, says cults often change their shape and name to avoid identification - and they can be found anywhere, even within mainstream churches. He advises students to be wary of approaches from anyone who is excessively friendly, who offers invitations to free meals or lectures "where the objectives are not clearly stated", and who have easy answers or solutions to world problems.
Research has shown that those drawn into cults are not the most vulnerable, weak or psychologically unstable - it is the confident and curious who are frequently caught...
Howarth was recruited into a cult as a 30-year-old businessman working in Canada. He was approached in the street by an attractive female recruiter to attend a meeting on "work in the community" and subsequently signed up for a course to become "a better person" and to give up smoking. Within days he had given up his job and the contents of his bank account to join the group.
"It was like being on a drug-induced high, I was blissed out." He left the group after only a few weeks - and after reading articles in a Toronto newspaper questioning its recruiting methods and financial irregularities. Even so, he says it took him 11 months to regain his sanity and self-esteem.
He argues that cults use sophisticated mind control techniques such as suppressing doubt by exploiting the need to belong; creating a sense of family through hugging, kissing, touching and flattery; constantly denouncing a person's former values and beliefs; maintainin g members in a state of heightened suggestibility through "meditation" (hypnosis), lack of sleep, fasting, repetitive indoctrination and controlled group experience; encouraging frequent confession of personal weakness and innermost feelings; burning bridges to the past through the donation of assets; promoting acceptance of the cult by promising advancement, power and salvation; maintaining loyalty through fear of damnation for the slightest negative thought, word or deed.
"The pressure on the mind is unbearable, " says Howarth. "What gives is the personality. People change dramatically. " For families and friends looking on, the effect can be devastating. Some feel that their son or daughter has undergone such radical transformation that they feel bereaved,particularly if they lose contact.
Tony Freeland, chairman of the trustees of CIC, lost his identical twin to a religious cult 25 years ago. "He was in his early 20s and he worked for the wine trade. He was approached on the street and six days later he had joined them. He changed totally - it was as if he didn't recognise me. He used to have tantrums in the house smashing things up, saying my parents were satanists. He is still with them. It is theft of mind, body and soul. It can destroy families."
A key part of the CIC's work is to give talks to school and college students. The Rev James Power, chaplain to Harrow School, calls Mr Howarth to talk to his upper sixth every year. "We usually find during these talks that several of our pupils have already been approached by cults. They come up Harrow Hill - the main road goes through the place - and we can't stop them.
"Young people will say that no one can be certain about anything, but deep down they are looking for certainty, and these groups provide that. One has to be so careful. Part of my job is to encourage them to take religious observance seriously but they have to be free to be critical, to question. There has to be room for debate."
Groups like CIC, FAIR - a support group for parents; INFORM - a government-supported charity that gathers information on new religious groups, and Catalyst - a cult counselling service - are overwhelmed with calls from desperate relatives and friends. The CIC alone has dealt with thousands of cases. Some parents resort to drastic action, including kidnapping.
Devotees who leave cults can suffer damaging, sometimes life-threatening withdrawal symptoms. Parents, teachers or friends helping somebody to find a way out should be extremely cautious and be careful about the help or counselling they draw on.
It is a murky world, full of accusation and counter-accusation, but some ex-cult members turned "exit" counsellors have been known to use deprogramming and restraining techniques that can lead to new dependencies and abuse. Moreover an over-zealous or mis-timed intervention can push a person back into a group and make them even more reluctant to contact family or friends.