Some children break up marriages, others traumatise their peers. Jack's main prey was his teacher. The eight-year-old, who refused to do anything without arguing and screaming, and stopped anyone else working, finally wore her out. When she started to talk about resigning, the head decided it was time to think about getting rid of Jack. But that's all in a nightmare past. Jack and his family have now moved out of the area, but the school remembers him not as its principal begetter of chaos, but as a pleasant and co-operative child eager to learn (see box below).
Rather than being consigned to the limbo of permanent exclusion, Jack -or, rather, Jack and his parents - were referred to the Marlborough. Three months later he had changed so much that his teacher was pressing to have him back in her class. He was another success for a new kind of professional - the teacher-therapist-who sees children's problem behaviour at school as rooted in family relationships.
Jack did not attend the Marlborough House Day Centre in Swindon, the subject of a much-discussed recent TV documentary about training disruptive children to behave reasonably. This was the other one, the education unit of the Marlborough Family Service in Westminster, known only to local teachers and the world's child therapy specialists. Its approach is more sophisticated and far-reaching than the straightforward behaviour modification techniques which Swindon uses so effectively. And the Westminster Marlborough takes on children old enough to do a lot of damage if they are violent, or, as they occasionally are, lethally inclined.
The Marlborough Family Service, which occupies a big, white, stucco villa in the leafy borderland between London's West End and Hampstead, has a major place in the history of psychiatry. Fifty years ago a pioneering doctor turned the house into a"psychiatric social club" which was later taken over by the NHS as the country's prototype day hospital for psychiatric patients. By the 1970s, the Marlborough was again breaking new ground by treating psychological disorders not as a problem of individuals, but of families.
The education unit was originally set up to provide teaching for the children of families undergoing therapy at the centre, on the same basis as schools are run in children's hospitals. But when primary teacher Neil Dawson arrived in 1980, on secondment from the Inner London Education Authority, he found that instead of just having to teach individual children he was given responsibility for their whole family.
The centre's director, child psychiatrist Dr Alan Cooklin, had decided that the education unit was the best place to handle families attending the centre because their children had been referred by their schools.
Brenda McHugh, primary-trained but with experience in secondary education, was working in the unit when Neil Dawson arrived. "The policy made sense," says Brenda. "It's far less threatening for parents to spend their time in a classroom interacting with the teachers and children than to attend a therapy centre. They come to trust us as teachers trying to help their children, and then to accept that they need our help in sorting out the family relationships which are at the root of the children's behaviour".
Plunging into therapy was not as daunting as it sounds, says Neil. As well as Brenda's example and advice, he received close support from the counsellors, doctors, therapists and other professionals at the centre. With their back-up, the two teachers undertook a four-year training programme and qualified as family psychotherapists.
Children are referred to the Marlborough - usually because their schools can no longer cope with their behaviour or they are constantly truanting - by Westminster's special needs assessment panel, which contributes Pounds 90,000 a year towards the unit's costs. The centre takes up to nine children, aged five to 16, at a time; they usually attend for around three months, although it can be as much as a year.
The children and any siblings spend four mornings a week in the unit's main classroom, while parents or other adult family members watch and listen from a comfortable lounge. Over cups of tea the adults chat about what is going on and - with increasing openness-about their own problems. With encouragement from the teachers, they will intervene to challenge or correct their children's behaviour when necessary. The whole family will from time to time attend sessions with the centre's psychiatrists and therapists.
"I think it's talking with the other parents that's the most important bit," says 29-year-old mother-of-four Melanie Gibson, who insisted on the family being referred; her eight-year-old son, Simon, had been stealing money at home and from school so that he could give it to his parents and teachers, pretending he had found it.
"You have this dreadful feeling of shame and isolation because you think, 'Why me?'. Then you come here and find that other people have the same sort of problems and you can help each other. It's a wonderful place and I don't mind you using my name because I'd be glad to tell anyone who needs help all about it."
The unit's work is based on a view of the child as having to operate simultaneously in two systems, family and school, which can often make conflicting demands and blame each other when the child cannot cope. The teacher-therapists aim not only to help the parents to see what is amiss within the family, but to understand how teachers relate to their children and to learn to collaborate with them.
Those children who have not been excluded return to their schools in the afternoon and for the whole of each Wednesday. The unit regards it as important for the children to keep up with their peers so that they do not rejoin the mainstream at a disadvantage.
Neil says that he and Brenda, with a part-time therapy-trained teacher who joined this year, manage to teach to the national curriculum, within the limits of their resources. They make a point of asking teachers what a child's classmates are currently studying so that they can cover the same ground.
Maintaining the trust of the local teachers is vital to their work. That calls for sensitivity when a child's problem is due in part to something that is going wrong in the school. While it is more common for parents to blame teachers for a child's misbehaviour, teachers have been known to scapegoat parents rather than examine their own role.
But that link must never be endangered, says Neil. "Our usefulness is entirely dependent on close collaboration with schools and the fact that we are teachers, therapists or not. If we lose their trust in us as professional colleagues, we're finished."