EXPULSION is every school's punishment of last resort.

No headteacher wants to disbar a pupil. But if that pupil's behaviour deteriorates to the point where it threatens school discipline and morale, then he or she must go.

It should be as simple as that, and in the independent sector it is. Tonight we report how St Peter's School headteacher Andrew Trotman acted decisively to deal with pupils caught supplying cannabis to classmates. After an investigation, four pupils have been expelled, and another four suspended for five days.

That has sent a clear message about rules and boundaries to the rest of the school, and ensured standards are maintained.

In the state sector, however, the issue is far more problematic. This is highlighted by the extraordinary case of the death-threat teenagers.

Two boys at a Surrey school repeatedly sent messages to a teacher saying they were going to kill him. A message left on his answerphone said "You are going to get stabbed in the back of the head."

At the very least, the boys deserved to be thrown out of school for conducting such a despicable hate campaign. Many would argue that they should also have been charged rather than just cautioned by the police.

Both 15-year-olds were initially expelled. But then an independent appeals panel overturned the headteacher's decision.

This is outrageous. No teacher at that school should be expected to teach boys who have threatened to kill one of their colleagues.

And if this is what they did to a member of staff, imagine how they could have terrorised fellow pupils. Allowing this thuggish pair to return would utterly undermine the teachers' authority.

Education Secretary Estelle Morris feels the same. She has intervened, but legally she has no power to stop the boys going back.

The case calls into question the judgement of appeals panels. They may have no direct experience of the disruption caused by the particular pupil concerned. The headteacher has, and their decision should be final.

Updated: 10:17 Friday, October 11, 2002