This shocking video shows the moment when a police officer drags a 13-year-old schoolgirl in handcuffs across the floor ‘like a piece of meat’ - all due to a silly school-gates row.

The Metropolitan Police have been accused of brutality after teenager Katelynn Murphy King was forcibly restrained and handcuffed by a policeman outside the gates of Wapping High School.

Footage captured on an iPhone by her twin sister shows the Green Spring Academy pupil being hauled across the pavement on her knees with her hands in cuffs.

Her family say police used unnecessary force and the IPCC has been called in to investigate.

Joan Whittaker, 51, Katelynn’s grandmother, said: “This policeman wasn’t tackling a grown man, this was a little girl of 13. It was extreme force and it absolutely was not justified.”

The schoolgirl was restrained after rowing with a 16-year-old pupil from Wapping High School who had allegedly goaded her and called her “a slag” before trying to kick her.

The twin sisters were visiting the secondary school in Commercial Road to meet a friend when the row broke out.

“My granddaughter lifted her hand as if to slap this girl,” said Miss Whittaker. “But there was no physical contact with these two kids, it was just two kids having a dispute and the policeman went too far.

“He came up behind my granddaughter. She didn’t know he was there and he restrained her on the ground and on her side in handcuffs.

“She’s not struggling, she’s compliant. She tries to get up and he just drags her like a piece of meat.”

She described the actions of the police officer as out of all proportion to the incident.

Katelynn’s family have released the video exclusively to the East London Advertiser in the hope of winning an apology from the Metropolitan Police.

“I believe the way he handled himself was disgusting,” said her grandmother.

“I think it’s really important that the whole thing is made public. It was very excessive. I would even say that it was a borderline assault.”

Katelynn was taken home following the incident at 4.15pm on October 5 and her family say she was not arrested or questioned.

She was left with badly bruised and swollen knees, a lump on her head, and bruises to her arms and torso.

The family, of Chambord Street, Bethnal Green, claim the policeman also tried to threaten Katelynn’s twin sister into deleting the footage from her mobile phone minutes after the incident.

They complained to police and the Independent Police Complaints Commissions (IPCC) has today decided an investigation should be carried out internally by the Met Police’s Directorate of Professional Standards.

A spokesman said: “The IPCC received a referral from the Metropolitan Police concerning an incident outside Wapping High School on October 5.

“Following a careful assessment we have decided that the incident should be locally investigated by the Metropolitan Police.”

A statement from Wapping High School said: “The police were called to an incident outside of school concerning the conduct of a student from another school in order to safeguard our students and members of the public.

“The matter is currently in the hands of the police.”

The Metropolitan Police said: “On Wednesday, October 5 police were called at 4.15pm to Commercial Road, Wapping, to reports of disturbance.

“Officers attended and arrested a 13-year-old girl on suspicion of affray and for a breach of the peace.

“She was de-arrested at the scene for the affray and taken home to prevent a further breach of the peace. “Once there she was subsequently de-arrested for the breach of the peace.

“The girl sustained minor injuries but did not require hospital treatment.

“On Friday, October 7 a complaint was received from a member of the public in relation to the arrest of the 13-year-old girl.

“This complaint was referred to the Directorate of Professional Standards who in turn referred it to the Independent Police Complaints Commission.

“Enquiries continue.”