It is not a new problem, of course. Children have always played in gangs, played with toy guns and toy swords, fought and been cheeky. Some have without doubt graduated to more serious violence. But the escalation of indiscipline, the growing general use of real weapons and the killing of Philip Lawrence in London is an indication of new interlocking factors, new complex influences which have become increasingly evident in recent years.

Any solution to the problem will depend on an understanding of these influences, an appreciation of their complexity and a willingness not to isolate just one as the root cause of all the trouble. It is not simply the fault of society, or parents, or teachers - or even the Government. In fact, “fault” or blame is far less useful than analysis in the search for a remedy for the problem.

The influence, or lack of it, of the home is recognised as pivotal to children’s behaviour patterns. Attitudes of many parents appear to have changed; in particular, the general lack of respect for all authority figures is reflected in their dealings with school and teachers. Reproof of a child for bad behaviour is often followed by a visit from a complaining parent. Despite this, it is not at all unknown for a parent bringing a child to a school’s reception class for the first time to express great relief that the child is starting school, because “I can’t do a thing with him” - this at the age of four-plus. Many parents act as if schools have no right to punish or even reprove badly-behaved children but at the same time seem to believe that teachers, not parents, are solely responsible for instilling good behaviour.

It is self-evident that larger classes coupled with the greatly increased expectations of schools and the workload of heads and teachers make it more difficult to spend time on individuals. Large classes didn’t matter all that much when children rarely moved from their desks, when the predominant teaching method was rote-learning and the curriculum was essentially confined to the bare essentials of the three Rs. The modern curriculum overload and the multiplicity of tasks that heads and teachers must now undertake cuts down the time available to deal effectively with pupils’ discipline problems. The underfunding which produces larger classes also reduces the number of people needed for dealing with those problems. Not surprisingly, there is a forecast of a severe drop in the number of those wishing to become teachers.

In addition to the reduction both of time and staffing resources, schools have also been severely restricted in the means they may use to deal with severe and persistent bad behaviour. I do not refer to the prohibiting of corporal punishment, which was always a dubious disciplinary remedy, but to the difficulties surrounding the exclusion, after all other sanctions have been painstakingly tried, of a chronically indisciplined pupil.

Exclusion is the last resort a head has in dealing with this intractable problem. It is protective rather than punitive in intent. It protects the rights of the other members of the wrongdoer’s class to an undisturbed education and often to physical safety. It protects, too, teachers’ safety, health and sanity.

There are at least four problems with exclusion which make it less than effective. First, if the school’s governing body reverses the head’s decision to exclude a pupil, the staff and children have to face a greater difficulty, that of a reinstated pupil who believes that the school has lost the battle against him. Second, the category of indefinite exclusion - for longer than the 15 days in one term of temporary exclusion - has been removed by the Government. The indefinite exclusion option allowed for time-consuming remedial action with the pupil out of school which heads and staff often found to be necessary to solve the problems of the pupil in co-operation with other school support services. Third, there is the enforced admission of an excluded pupil to another school and the consequent problems. Fourth and most important, there is little if any provision by local authorities or the Government for disruptive pupils who are habitually excluded from one school after another. These are the ones who are likely to be found wandering the streets, a danger to themselves and others.

It is customary to apportion blame for teenage violence to the influence of the media, particularly television. It is certainly true that children, even very young children, have a vastly increased knowledge of human aberrations and that there has been a significant relaxation of parental supervision or control of children’s watching of TV programmes or videos. The impact of their visual experiences shows itself in copycat behaviour in school playgrounds following particular violence fashions on television. This influence is largely out of the school’s control.

There are two hidden obstacles to our complete knowledge of the true extent of the discipline problems facing our schools. First, there is a natural reluctance on the part of heads and staff to promote copycat behaviour by publicising examples of indiscipline. Second and more seriously, the true picture is often deliberately hidden because of the detrimental effect on a school’s good name. A reputation for bad behaviour or a large number of exclusions may seriously affect the number of admissions to the school and therefore the school’s funding position.

Four afterthoughts: Most schools are still safe havens for children but many are only such at the expense of the extraordinary effort and stress of beleaguered heads and teachers.

Some years ago, following football riots by teenagers, one teachers’ leader commented that the vast majority of the Saturday rioters who had given the police such problems would be sitting quietly in the schools on the following Monday.

In times past, pupils depended for a job on exam results or at least upon a “good character” reference when they left school. No reference is needed to draw the dole.

A paid job changes the status of a young person from child to adult. The absence of this change leaves a youth in a sort of no man’s land. No wonder the gangs hang around the school, the last place they really belonged to.

And a question: If Philip Lawrence had survived, would he have been charged with assault?

John McNicholas is former president of the National Association of Head Teachers.