Katelynn Murphy King can be seen being restrained by force and handcuffed after an argument with an older pupil who called her a “slag”.
Katelynn’s outraged family say police used unnecessary force and have slammed them for brutality after her twin sister filmed the drama outside the school gates in East London.
The Independent Police Complaints Commission has been called to investigate.
Her family, of Bethnal Green, said the policeman also tried to threaten Katelynn”s twin sister into deleting the footage from her mobile phone minutes after the bust-up.
They complained to police and the IPCC has today decided an investigation should be carried out internally by the Met Police”s professional standards team.
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.”