But even within primaries and secondaries, a high number of classroom incidents involve pupils with special educational needs.

Figures on violence against staff released by the Scottish Executive show a steady increase in the number of reported incidents, rising from 1,898 in 1998-1999 to 5,412 in 2001-2002. Overall, 237 incidents, or 4 per cent of the total, were reported to the police.

Authorities say that better reporting, recent training and a greater willingness by staff to record incidents have probably led to the increases, although there may still be under-reporting.

The Scottish Executive observes that school staff may have different responses to incidents and what one member may report, another may choose not to. Figures confirm that there are more incidents in special schools (1,727) than in secondaries (1,602) but marginally fewer than in primaries (1,982). Proportionately, both teachers and support staff in special schools are far more vulnerable.

Drawing comparisons between the sectors, statistics show that there were 21,105 incidents in special schools per 100,000 pupils. There were only 472 in primary and 507 in secondary.

In 94 per cent of all reported incidents, the perpetrator was a pupil at the school, leading to a rate of six incidents per 1,000 pupils. Where information was available, 60 per cent of these incidents involved pupils with special educational needs.

Virtually all incidents are within school hours and half take place in the classroom. Physical violence accounts for 44 per cent of incidents, 26 per cent involve physical and verbal abuse, and 29 per cent involve verbal abuse alone.

Two-thirds of incidents involve teachers - but in special schools 849 teachers were involved in incidents, against 793 non-teaching staff.

Sometimes both were involved at the same time.

Cathy Jamieson, Education Minister, said that teachers had a right to do their jobs without fear of physical or verbal abuse, one of the reasons why the Executive was investing pound;10 million a year to improve behaviour following the report of the discipline task group.

Some of the measures such as pupil support bases, additional staff to supervise pupils between lessons and home-school link workers would make a “real and lasting difference”, Ms Jamieson said.

“It is important we have accurate details of incidents. If staff feel more able to report these incidents in the knowledge that they will be properly recorded and dealt with, then that is a very welcome development. We will continue to improve the way we collect data and ensure that we target resources on improving school discipline.”