A shocking video has shown the moment a young prisoner was brutally beaten up by his fellow convicts inside their cell even as he cries for help.
The footage, which is thought to have been filmed in HMP Brixton in London shows a 25-year-old man being repeatedly hit around the face, as he is filmed on a contraband mobile phone.
It is believed the clip came to light when it was posted on Periscope, a video sharing site.
The footage, which lasts a minute and a half, starts with the young inmate being pinned down on the ground while another prisoner slaps him across the face as he cries out in pain.
One of the men can be heard telling the beaten man to 'sit up and stop screaming' as the camera pans around the cell, where loud music is being played.
He is then pulled up in a head lock and made to sit down in a chair before he is warned: 'If you scream like that again, you're going back down there.'
The man is then told to calm down and 'fix yourself' before being ordered to wash his face in a sink.
As he sobs while throwing water over his face, an inmate asks: 'Do you know where you are? You are in Brixton you know. Clean up!'
The victim then tells another man holding a mobile phone a code to enter into the device and then tells another prisoner: 'I didn't do anything, it wasn't me it was my people down low.'
But this infuriates the man, who orders the frightened inmate to move his hand and 'put his face up' before he strikes him again on the face.
He then sobs out loud before the clip ends with him being told to 'fix himself' again.
Daily Mail UK reports that police confirmed they are investigating an allegation of assault at Brixton Prison earlier this month on March 4.
Meanwhile the Prison Service said the attackers have been stripped of their privileges and will be moved to other prisoners.
A spokesman said: 'This behaviour is totally unacceptable.
'We have identified those involved and they have been stripped of their privileges and will be moved to other establishments as punishment.
'As the Prime Minister and Justice Secretary have said, our prisons are in need of reform.
'That is why we are investing £1.3 billion to transform the prison estate over the next five years, to better support rehabilitation and tackle bullying, violence and drugs.'