One problem is that many teachers are no longer sure whether they are legally entitled to physically restrain an indisciplined pupil. A supply teacher who took action against a disruptive pupil last year was suspended without pay for six months, before a Hampshire court found him not guilty of assault.

The law on restraint is set out in Section 550A of the Education Act 1996. Staff authorised by the head may now use such force as is reasonable to prevent a pupil from committing a criminal offence, or averting an immediate danger of personal injury to themselves or others, or damage to property including their own, or to prevent behaviour prejudicial to the good discipline and order of the school.

This has never fully allayed teachers’ anxieties, because there is no legal definition of “reasonable force”. From Circular 1098, it appears to be the circumstances of a particular incident that are important. The use of physical force to prevent a trivial misdemeanour cannot be justified.

Moreover, force used must be in proportion to the severity of the incident, and must be the minimum necessary to gain the desired result. Examples of situations where physical force may be justifiable are: violent behaviour to another pupil or member of staff, acts of vandalism, misbehaviour such as rough play, or a disruptive pupil’s refusal to leave the classroom.

Teachers are urged to take great care over the use of force, and always try to resolve the situation by other means. The circular is emphatic that staff should not cause pain or injury by striking or holding a pupil around the neck, or pulling hair or ears.

This is all very well when staff have time to think. In reality, many situations happen in a twinkling. If two boys are beating the living daylights out of each other, many teachers will instinctively step in and haul them apart. It is quite likely that any court would deem the teachers’ reaction to be justifiable. But what if the teacher then continues to hold one of the pupils while telling him what heshe thinks of the behaviour? Has the situation then moved from “justifiable restraint” to “corporal punishment”, simply by prolonging the contact?

Ultimately it would be up to a court to determine whether it was justifiable or not, and judges have so far generally backed the teacher. But this is not a particularly satisfactory situation and there have been too many investigations into trivial incidents.

In the public care system and in schools which deal with children with emotional and behaviouraldifficulties, physical restraint is highly regulated, and training in restraint techniques is mandatory.

It is clear that all schoolteachers would benefit by receiving better training in this area.

Chris Lowe is honorary legal consultant to the Secondary Heads Association and editor of Croners’ School Governors’ Manual