Undercover filming reveals prison in crisis
Secret filming for the BBC has revealed chaos in one of the biggest prisons in England and Wales.
An undercover reporter spent two months inside HMP Northumberland for the BBC's Panorama programme.
He discovered widespread drug use, a lack of control, door alarms that did not go off on one house block and a hole in an internal security fence.
The Ministry of Justice has said it will investigate the "extremely serious allegations".
Watch Panorama Behind Bars: Prison Undercover on Monday 13 February at 20:30 GMT on BBC One. Or catch up on iPlayer.