UK teachers said yesterday that the only way to tackle cyber bullying in schools is to close websites such as YouTube, which encourage such behaviour.

Speaking at the Professional Association of Teachers (PAT) annual conference yesterday, Kirsti Paterson of the Highland & Western Isles Federation SEC Committee, said that bullying had transcended the playground and moved into the digital realm.

"As we move further into the 21st century, we are also recognising a new form of bullying, manifesting itself in the misuse of mobile phones. The majority of young people possess the newest and most hi-tech gadgets, increasing digital interaction. Such technological advance has also brought the threat to which I make reference in my motion – cyber bullying."

Paterson said that cyber bullying ranged from texting threatening messages to using camera and videophones to take pictures without permission. She said that such videos have been discovered on the YouTube website. Meanwhile access to internet sites such as Rate My Teacher is also being used by pupils to make hurtful and offensive comments about school staff.

In one incident, pictures of a staff member were taken during a class lesson and posted on a website, with the accompanying caption: "YOU ARE DEAD".

In another, a pupil put derogatory comments about another pupil on a website but portrayed it as though it was a staff member who had published the offensive remarks.

"Nowhere is safe from cyber bullying. It can carry on 24/7 through mobile phones and in multiple forms online. Remarks, images posted online can be easily copied and can be present on line in many places. To quote our general secretary, Philip Parkin, 'Cyber bullying is an invasion of privacy from which it can be difficult to escape'," Paterson said.

In the short term, Paterson proposed the closure of sites encouraging the cyber bullying but in the long term, she said authorities and schools must have policies encouraging responsible and safe behaviour online.

According to a recent study carried out by Goldsmiths University, between a fifth and quarter of students surveyed had been a victim of cyber bullying at least once over recent months.