The fact that more than 900 people ‘liked’ footage of a sickening attack on a teenage girl posted on to a Facebook page speaks volumes about the sinister trend of cyber bullying.

When bullying goes online, it brings out a disturbing voyeurism in people. Social media has its uses, and it seems one of them is turning bullying into entertainment.

With national research showing that one in three pupils has been a victim of cyber bullying, it has become a major issue for schools.

As reported in the Telegraph & Argus this week, a shocking mobile phone video of an attack on a teenager by another female pupil at Beckfoot School came to attention when it was posted on a Facebook site. The incident, described as an “exceptional and serious” case of cyber bullying, is under investigation by police.

The clip, accompanied by a jeering message, shows pupils surrounding a 14-year-old girl who is pulled to the ground by her hair and repeatedly thumped. She suffered minor facial injuries in the attack.

Within two hours of the video appearing online, nearly 900 people had ‘liked’ it – which, in cyber speak, means they either literally liked it or acknowledged it – and 595 users had shared the link.

The Facebook page was removed this week, but the footage has caused outrage and Beckfoot School has been inundated with calls and e-mails.

Headteacher David Horn said the school was taking “appropriate action” in line with its behaviour policy.

Ian Murch, Bradford-based national executive member of the National Union of Teachers, said the effect of cyber bullying was traumatic. “It will often be a long time before someone realises that this behaviour is going on. It’s very bad for children’s mental health,” he said.

Councillor Ralph Berry, Bradford Council’s executive member for children and young people’s services said the “exceptional and very unusual” incident was being taken very seriously.

One of those shocked by the video was trainee teacher Charlotte Faulkner, who had a friend who committed suicide because of bullying. Of the Beckfoot pupil video, she said. “It has become almost an internet ‘sensation’, which outrages and disgusts me further.”

Facebook declined to comment, but pointed out a tool on every page where people can report offensive material. Staff look at complaints and can remove posts of harassment and close down profile pages.

Susan Chambers of Gomersal, whose daughter was a victim of cyber bullying when she was a young teenager, said she felt sick reading this week’s T&A report. “It brought back chilling memories. My daughter was repeatedly picked on and we knew nothing about it. It was only when someone filmed her crying, and put it online, that we were alerted to it. I was horrified. She looked like a frightened little girl, and someone thought it would be amusing to film her with their mobile phone.

“These bullies are callous beyond belief and need to be stopped. Schools should make it a priority to crack down on this behaviour.”

A total of 344 bullying incidents were reported by schools in the Bradford district between September 2010 and July, 2011.

This week, an anti-bullying campaign run by the charity Family Lives secured nearly £3,000 thanks to a partnership with Bradford-based OfficeXpress. The money will go to the charity’s BullyingUK project supporting people who have been bullied at school, online and in the workplace.

Family Lives advises parents to monitor their children’s Facebook sites. “If you join up then you’re inviting total strangers into your home!” says the charity’s website.

The charity warns of potential internet-related dangers, such as grooming, and stresses the importance of controlling who sees your Facebook profile.

It also tackles mobile phone bullying, identifying it as silent calls, insulting and threatening texts, abusive verbal messages and stolen identity. Advice includes logging calls, not replying, and reporting them to the police.

“Cyberstalking is frightening and illegal and the people who do it are not as anonymous as they think,” says a charity spokesman.

The charity also offers advice on using internet chatrooms: “When you join, you’ll find people are very friendly, but how do you know that John aged 14 who wants to be your new best friend really is a teenager and not Frank aged 57?”

Family Lives’ internet safety tips include never giving out your real name, address or telephone number; never telling anyone where you go to school; and only meeting someone from a chatroom in a public place with a parent or another adult present.

Visit www.familylives.org.uk.