Students are increasingly using the internet's social-networking sites to harrass and bully their teachers and lecturers. A UK university has written to all its students threatening them with disciplinary action for personal comments about its staff online.

Keele University said the remarks on popular networking sites such as MySpace and Facebook were unacceptable, and students may face legal action from the members of staff concerned.

Pupils should used "legitimate ways" to express dissatisfaction, they added.

A bucket of water over the door? Loose leg on teacher's chair? Dog mess wrapped in burning newspaper left outside Sir's front door?

These traditional ways of expressing dissatisfaction work better in their space than in MySpace.