Teachers warn of online threats from pupils
Social networking websites are being used to threaten and make false allegations against teachers, according to a teachers' union.
The NASUWT says a survey shows that more than four in 10 have experienced such online abuse.
Pupils and their parents have carried out such online attacks - many of which go unreported, say teachers.
A spokesman for the Department for Education said such website bullying was "completely unacceptable".
Chris Keates, general secretary of the NASUWT, described the level of online abuse against teachers as "truly shocking".
The teachers' union, holding its annual conference in Birmingham, says that teachers have even faced death threats from pupils writing on websites.
There have been false allegations of "inappropriate behaviour with a pupil" and attacks on teachers' professional ability, according to the survey.
According to the research, 16% of teachers had faced online insults from parents.
When such parents were reported by teachers, fewer than a third thought that adequate action had been taken against the culprits.
Facebook was identified by teachers as the social networking website most used by pupils to comment about school staff.
But a Facebook spokesman said: "When conversation crosses a line and turns into harassment, teachers have access to reporting tools on almost every page of the site, unlike much of the wider web."
Ms Keates said even though this was such a serious problem, "there are no adequate procedures in place locally or nationally to protect teachers".
"It is clear that some employers are seriously failing in their duty of care by neither having appropriate policies in place nor taking incidents seriously when reported."
She accused the government of being "seriously wanting" in how it responded to such cyberbullying.
"It is absolutely unacceptable for pupils to bully, threaten or abuse teachers," said a spokesman for the Department for Education.
"False or malicious allegations about teachers not only damage careers but ruin lives.
"The provisions in the Education Act - as part of a wider package of measures on behaviour in schools - help put teachers back in control of the classroom."