When Emanuel Tabachnick, a teachers’ union attorney in the US, addresses seminars on defending those accused of child maltreatment, he always tells of his high school days. A poor maths student, he got through only because a woman teacher voluntarily met him before school and taught him in a room alone. “It breaks my heart, but when I talk to teachers now I tell them never to be alone in a room with a student,” he says.

Psychologists Elizabeth Anderson and Murray Levine, of the State University of New York, surveyed more than 3,000 US teachers and found 56 per cent were aware of false allegations made against a teacher in their school district. About a third (36.5 per cent) expressed concern that such allegations could be made against them; 42 per cent advised a new teacher against being alone in a room with a student; 62 per cent against casual touching; 70 per cent against hugging or putting an arm around a student.

False allegations usually fit into two categories: one in which children come up with the claim themselves, the other where the accusation is suggested by a parent or another figure in authority. For example, perhaps a parent has made an enemy of a particular teacher and coerces their child to allege impropriety. The child would not have made the allegation if left alone; it’s the pushing parent who is the real culprit.

It could be that a parent becomes jealous of a teacher; they feel he or she has gained more respect and influence in their child’s life than they have.

A false allegation breaks up a relationship which, from their point of view, has become too close for comfort. The desire is to cause as much mischief as possible, or to force the dismissal of a teacher who has become perceived as an enemy. Or the teacher is seen as responsible for a child not taking a desired course, or failing to attain a hoped-for objective.

This kind of deceit is often uncovered by psychologically seasoned investigators questioning the child with another supportive, but more neutral, adult present. Away from his or her parent, the child’s story and resolve will tend to break down.

Psychiatrists divide the main motivations for making false allegations into “primary” and “secondary” gains. In primary gain, the accuser benefits directly by receiving attention and care; “victims” in today’s culture get a lot of attention from authority figures, such as the police and lawyers.

Secondary gains flow more indirectly from the allegation; perhaps the child gets to stay away from school or a disliked teacher will be unable to discipline him or her. The allegation is a kind of power game.

But sometimes more subtle forces are at work. A classic motivation is the allegation as distraction. Perhaps the child has done something wrong and is worried about being found out. An allegation against a teacher distracts attention from other possible explanations for their misdemeanours. They want to divert attention; the awfulness of the allegation drowns out any concern about their wrongdoing.

It is vital teachers get a sense of the psychology behind false allegations. The children who make them can be deeply disturbed and hostile, but these claims can also arise out of pre-existing scenarios where powerful but often covert emotions such as jealousy, anger, conflict and emotional deprivation play a role. The irony is that those pupils perhaps most prone to make them are also those who concerned teachers try to help most. Their desire to intervene means they may not take necessary precautions and so innocently risk the nightmare of a false accusation.

Dr Raj Persaud is a consultant psychiatrist at the Maudsley hospital and senior lecturer at the Institute of Psychiatry in London. He is the author of From The Edge of the Couch: bizarre psychiatric cases and what they teach us about ourselves (Bantam Press, pound;12.99), which explains false allegations, and other psychological phenomena. Email: rajpersaud@tes.co.uk