If the statistics are to be believed, the safest place to teach in Scotland is Glasgow, while those most at risk of being assaulted by pupils are in Aberdeen schools.

Glasgow, with the most deprived communities in Scotland, reported eight incidents of violent attacks on teachers in 2006-7, out of 1,221 cases which involved verbal as well as physical abuse of teachers. Only Orkney, which has had just one murder in the past 40 years, reported fewer violent incidents (four).

By contrast, Aberdeen teachers suffered from 761 violent attacks - out of 761 - which means all incidents were deemed to be physical.

The difficulties in defining assaults on teachers, and giving consistency to the figures across Scotland, were key reasons the previous government at Holyrood decided to stop publishing them annually, pending a fuller investigation of what they actually meant.

The SNP administration says it is reviewing that decision. A spokesman acknowledged that definitions and reporting are unreliable: “We want data to be comprehensive and consistent so that we understand the levels and seriousness of indiscipline in our schools.”

The latest figures were unearthed following a Freedom of Information request by the Scottish Conservatives. They now want “this vital factual information” republished every year.

But the “factual” nature of the information continues to be in doubt. Aberdeen, for example, told The TESS its figures had been inflated by including special schools, with some of the most disturbed youngsters, for the first time. The council said it had 1,153 verbal and physical assaults on teachers in 2006-07, of which 384 were in special schools. These figures do not accord with the Fo... data.

A Glasgow City Council spokesperson said it recognised there appeared to be “inconsistencies and variations across the country and we welcome any proposal designed to bring greater clarity”.

The key to understanding the figures lies in discovering how “violence” is interpreted, and whether it describes “violent assault” or “violence towards” teachers. One official said schools have been known to record as “violence” cases where pupils told teachers to “f*** off.”

Overall, 29 of the 32 authorities which submitted the information they were asked for showed 4,608 attacks on teachers “with a physical element”, out of 7,306. These represented increases of 2.2 per cent and 4.3 per cent respectively.

Meanwhile, the interest groups responded to suit themselves. The Tories called for more powers for heads to exclude pupils, the Educational Institute of Scotland said smaller classes were the answer, the Scottish Secondary Teachers’ Association said the figures could be the tip of the iceberg because of pressure on schools not to report incidents, and the Convention of Scottish Local Authorities believed the increased figures were due to more reporting, not less.