Cyber bullying is having a serious impact on teaching staff in Northern Ireland, a union has warned.
One in six teachers is the victim of cyber bullying
The NASUWT has said pupils are filming teachers on mobile phones on a daily basis and posting them on the internet
A government report said that more and more teachers are falling victim to the practice. The union's Seamus Searson wants mobiles banned from schools.
"It destroys their confidence and we have found members who are reluctant to go back to school," he said.
"In the worse case scenarios we have had examples in England where teachers have committed suicide as a consequence of it."
One in six teachers in the UK is thought to be the victim of malicious text messages and internet postings sent by their pupils.