When science teacher Vilma Elliot’s older daughter went off to university, she felt a sense of satisfaction. “You feel you’ve achieved something, that they’ve come this far and are making their own life,” she says. Two and a half years later, the family’s hopes lie in tatters. Kate Elliot was recruited by a millennial cult last year; her family have had barely any contact with her since and recently marked her 21st birthday without her.

Vilma Elliot, 45, describes the shocking speed with which her daughter disappeared from her life last summer. “She came home at the weekend, near the end of term. She was out in the garden on Sunday doing exercises and she told our neighbour that she was going to go on to do an MA, a PhD and whatever else it took, she was enjoying university so much.

“The next evening, she was back at college and these people came for her and sped off with her in a vehicle. Two weeks later we had a letter full of biblical quotes saying she was going to do God’s will and nothing would stop her. It wasn’t her at all. I felt devastated that it was even written in her handwriting. We found out later that it was a standard cult notification letter.”

Vilma Elliot has learned a lot about cults since then. She believes the group made initial contact with her daughter on the streets of the university city where she was living, and then quickly moved to recruit the young woman she describes as loving, outgoing and optimistic. “She was such a warm person,” says Vilma. “Always lively and having fun.”

She talks about her daughter in the past tense, believing that Kate’s personality is likely to have been utterly changed. “I know that they have turned her against us,” she says. “They wanted to isolate her from her family so they could control her behaviour, disorientate her and create a situation where to stay sane she would have to accept their beliefs.”

The family believes Kate is now in the US; despite sending almost daily e-mails to her through the group’s website, they have not made contact; the cult requires members to renounce family, friends and work. “The image I’ve got of her is that she’s working seven days a week out on the streets giving out leaflets and taking donations,” says her mother. Families of cult members have described the experience as a living bereavement.

The horrific recent events in Uganda, in which at least 1,000 people either committed suicide or were killed, apparently on the orders of two charismatic leaders, are a tragic reminder of the extreme dangers posed by cults. Followers of the Restoration of the Ten Commandments of God believed that their leaders - two excommunicated Catholic priests - talked directly to God.

Before the Ugandan horror, the biggest cult-related slaughter occurred in 1978 in Guyana, when 914 followers of Jim Jones’s People’s Temple drank poison. But, as the end of the millennium drew closer, there was a sudden proliferation of such tragedies. In 1993, 70 members of the Branch Davidian cult died in a fire at Waco, Texas; 69 followers of the Solar Temple cult died in incidents in Canada and Switzerland in 1994 and 1995; in March 1995 the Aum Shrinriko killed 12 commuters with nerve gas on the Tokyo underground; and three years ago, as the Hale-Bopp comet passed Earth, 39 members of the Higher Source group killed themselves in California.

Cult experts believe that up to 1,000 cult or cult-like groups are operating in the UK. The groups, many of which are international, are secretive, highly litigious and change their names frequently; accurate measurement of numbers is impossible. Some come out of established churches and religions, others are therapy-based, or espouse New Age philosophies. What they all have in common is manipulation of their members. Yet few young people get any education about how to spot cults, and their methods of recruitment.

Ian Haworth, 52, is general secretary of the London-based Cult Information Centre (CIC), an educational charity he set up after his own experience of being briefly recruited into a cult in Canada in the 1970s, via a seemingly innocuous course to quit smoking. He was hypnotised four times in the course of the two-day programme, he believes, and on the following Monday resigned from his job as a communications consultant to join the group. Colleagues were so bewildered by his behaviour that they thought he must be on drugs. “People don’t join cults; they are recruited and then forced to stay,” he says. “Most cults can recruit and control a person in a matter of three or four days.”

Ian Haworth gives talks in schools on “destructive cults”, warning pupils that the popular idea that only very vulnerable people join cults is wrong. Talking to lower sixth-form pupils at Graveney - a 1,700-pupil, 11-18 foundation school in south London - he tells them that “intelligent, well-adjusted people get involved in these groups”. He warns that recruiters work college and university campuses and towns, sending young, attractive people out with free magazines or invitations to meetings with “like-minded people”. The psychological coercion which follows can be the result of hypnosis, sleep deprivation, verbal abuse, isolation and so-called love bombing, which aims to disorient the potential recruit and break down any physical and mental resistance.

The Graveney pupils, in ponytails and jeans, listen attentively. “Cult members should be viewed as victims,” he tells them. “I don’t recommend giving them a hard time. I don’t recommend giving them money. There are plenty in this area.” Afterwards a few students come up to talk to him; one has been approached by one of the groups named.

Students are particularly at risk from religious cults, whose typical member is young, well educated and idealistic, says Ian Haworth. In its 1990 publication, Shining Like Stars, the London Church of Christ describes campus ministry as “the goose that laid the golden egg”. In the first two weeks of the academic year, adherents recruiting for the group are advised to “set personal goals of between 10 to 20 new acquaintances each day. By making the most of these precious days you will surface the maximum number of open contacts.” There is an openness to new relationships at university that will fade dramatically within the first two weeks, the book explains.

Graham Baldwin runs the anti-cult charity Catalyst, which provides counselling, legal advice and training to families and individuals affected by cults. He believes there has been a growth in the number of smaller cults, which sometimes consist of just a charismatic leader with a handful of followers. “The change has been away from the big groups to the more esoteric, smaller, hidden groups. Some are offshoots of Christian churches, some are more New Age.” Catalyst is hoping to employ an education worker to go into schools and talk to sixth-formers. “It’s not to say ‘don’t believe in religion’,” he says. “The message is that as students you will be targeted, be on your guard and if you go to a meeting don’t check in your brain at the door.”

The subject of cults and how people get out of them is touched on in the new film Holy Smoke, starring Kate Winslet and Harvey Keitel. The film has disappointed anti-cult campaigners with what they see as its misleading portrayal of the work of exit counsellors. In the film, a cult member (Winslet) is imprisoned by a cult-buster (Keitel), whom she then seduces.

In reality, says Graham Baldwin of the charity Catalyst, which provides exit-counselling, coercion does not work. Kidnapping as a way of getting people out of cults is also discredited, says the former university chaplain, and very rare. “We want people to get to the point where they take control of their own lives. The whole process is about the person having the freedom to choose and I will only talk to them if they agree to talk to me.” Catalyst takes on an average of five new cases a week, and has about 100 at any one time.

In the months after Kate Elliot disappeared, normal life was suspended for her family as they toured England hoping to find Kate and be allowed to talk to her. Now, Vilma is back at the Midlands comprehensive where she is a head of department. At home, she has started cooking and cleaning again. But her younger child has dropped out of school as a result of the trauma the family has been through, and suffers from nightmares. Vilma carries a sheath of photos of a younger Kate - in the woods, on the beach, a smiling child with her arms round her younger brother - in her bag. She is getting used to the idea of a long-term campaign to free her daughter. “I do have hope that we will see her again,” she says. “But I don’t think it will be soon.”

Staff at her school have now introduced a cult-awareness talk for older pupils. “You prepare your kids for everything,” she says. “You teach them rights and wrongs, give them information about drugs and alcohol, do the sex education bit and the condoms bit. Because of the profession I’m in, I’m mortified that we hadn’t prepared her for this. I hope that people in education will sit up and take notice and realise that this can happen to any of the students that we teach. All it takes is for a group to target them and for them to lack information.”

The names and details of the Elliot family have been changed. Cult Information Centre, BCM Cults, London WC1N 3XX. Tel: 01689 833 800. Website: www.cultinformation.org.ukCatalyst, Thames House, 65-67 Kingston Road, New Malden, Surrey KT3 3PB Tel: 020 8949 7877