A dangerous craze where children are filmed being attacked by other kids at school could lead to a child being killed.

That’s the warning from the half-brother of a 13-year-old girl who was dragged to the ground by her hair and kicked in the head by other youngsters.

The victim was just leaving for home after school when she was attacked only metres from the gates.

A video online shared by children in Rochdale before Easter shows the assault.

What looks like around two dozen other children are gathered around baying and jeering. An adult witness told Sky News there were around 40 kids present at the attack which experts say is becoming a “sickening” and “growing” trend in Britain’s schools.

The motive for the attack was quite possibly the videos themselves – a moment of notoriety on social media, creating content to be shared and laughed about in private groups on Snapchat.

A fair number of the children present had their phones out filming. Many seemed to know the ambush was coming. At least one of those filming also joined in on the assault, kicking the victim while she was on the ground.

Even the victim had found out via social media that there was an attack planned.

It’s part of what the National Bullying Helpline told Sky News was an “escalating problem of children filming violence against other children then uploading to social media”.

Courageously, the 13-year-old girl who was pounced on just before the Easter holidays wanted to speak out about it – but we’ve agreed not to name her or show her face, even though she accepts everyone in her school knows what happened.

She described how she felt afterwards. “I had a black eye. My head hurt every time I spoke. I couldn’t laugh because my head hurt. I couldn’t move my neck. My back was sore. I have a scar on my knee that they cut open.

“I don’t really like walking around now where I know people from the school are going to be, because pretty much everyone in my school knows about it. And I’m kind of glad that I don’t have a phone because I feel like I’d just be getting messaged about it all the time.”

She no longer has a phone because her attackers stamped on it.

Attacks ‘getting more vicious’

Billy, 44, the half-brother, and legal guardian of the victim says this is becoming a dangerous craze.

He told Sky News: “They pick on someone who’s normally quiet, somebody who doesn’t bother anybody, they’ll then use that person as a target to create this online content. And it’s getting more vicious as each attack comes.

“I don’t believe my sister has any long-running rivalries within the school. I believe this was created solely for the content of the internet.”

He added: “A child is going to lose their life from this craze. It’s happening all over the country.”

Christine Pratt, the founder of the National Bullying Helpline, said: “Increased calls to the National Bullying Helpline flag up this increasingly popular, but sickening, trend.

“This particular behaviour [filming abuse to upload to social media] is seen as ‘sport’ and amusement, often led by gangs and school bullies who seek power and attention. It is classic bullying.

“When it is posted ‘online’ the abuse takes a new form. The victim is further ridiculed. Once on social media, it is ‘out there’.

“We hear about this practice occurring most weeks. It is usually the parent who calls us. They often struggle to persuade a school to believe them and/or take it seriously, investigate or deal with the perpetrators.”

One head of school in a well-known private school in London recently sought advice from the helpline, after a filmed attack happened in the boy’s toilet and was observed by over 20 students.

Not one of the onlookers felt safe enough to report it at the time and it only came to light a month later. The headteacher introduced initiatives to unite the pupils and encourage ‘bystanders’ to feel comfortable enough to report future incidents.

For safeguarding reasons, we have decided not to name the school in Rochdale, near where the Easter attack happened, but parents have told Sky News there have been several similar incidents just at or near this one school.

One woman who walks past every day to collect her children from a nearby primary school said she had intervened in four similar attacks.

Another mother, who wishes to remain anonymous, shared with Sky News a video of her daughter being attacked in January by a group of girls on the school premises.

Prior to the attack, a phone camera is switched on and propped up, pointing in the direction of the teenager who is about to be punched. The girls can be heard plotting. “Can you see her?” “Are we doing it or not? Are we doing it outside or in here?” “Go on then, go on then.”

After a brief verbal assault from one girl, another punches her then pulls her to the ground by her hair.

Another mother at the same school, who didn’t want to be identified, told us last term her son was randomly attacked by more than a dozen children on the playing fields – and she feels the school is failing in its duty of care.

She said: “From them kids coming into them gates at 8.20, they’re there to safeguard our children and they’ve failed to do that.”

The headteacher of the school we’ve decided not to name told us: “These stories will, of course, concern families who are part of our school community. Mutual respect, positive behaviour, and high standards are central to everything we do.

“In cases where members of our school community fall short of the expectations of leadership, staff, pupils and their families, nationally guided procedures are followed.”

‘We take extremely seriously our duty of care’

The headteacher added: “The incidents referenced by Sky News are both subject to ongoing enquiries either by the school or a third party. As a result, we won’t be providing further comment on those at this time.

“We take extremely seriously our duty of care to our young people and our local community. As such, staff have a high visibility presence within the school grounds and the immediate vicinity of – before, during and after school.

“We have processes in place to ensure a robust response to disclosures made regarding the safety of students and our post-incident procedure includes the administration of first aid by trained members of staff.”

Greater Manchester Police (GMP) said: “We would encourage anyone who is subject to offences on social media that encourages violence against another human being, to have the confidence to report them immediately to GMP via 101 or 999 in an emergency.

“Greater Manchester Police is committed to investigating each and every complaint received of this nature and bringing the perpetrators to justice, because those who are inciting violence through the use of social media, are committing crimes.”

Sky News understands the attack on the 13-year-old is now being investigated by the police. But the National Bullying Helpline says schools and authorities are failing to keep pace with this growing UK-wide problem.