Katelynn Murphy King was tackled to the ground as she was arrested outside the gates of Wapping High School in east London on suspicion of affray and breaching the peace.

She was restrained after rowing with a 16-year-old pupil from the school who allegedly called her a “slag” before trying to kick her. King reportedly raised her hand as though to slap the other girl, but there was no physical contact between them.

The officer then came up behind King and restrained her on ground.

The footage, shot by King’s twin sister, shows her being dragged by her hair in what the family have called “unreasonable force,” even though she appears to be complying with the officer.

King’s grandmother Joan Whittaker has labeled the police officer’s actions “disgusting” and “out of proportion to the incident.”

“It was just two kids having a dispute and the policeman went too far.

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

“This policeman wasn’t tackling a grown man, this was a little girl of 13. It was extreme force and it was absolutely not justified,” she added.

“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.”

The Metropolitan Police confirmed the incident has been referred to the Directorate of Professional Standards and a complaint was lodged.