More than 70 young offenders have been moved after a wing at a prison was flooded during a disturbance.
The prison houses young adults and youths
The Home Office has confirmed that a disturbance took place on Wednesday night at HM Prison Hindley.
In a statement, it said about 26 prisoners refused to return to their cells and proceeded to flood a wing of the jail, in Wigan, Greater Manchester.
Negotiators were sent in and the incident ended early on Thursday, with about 76 inmates moved to other jails.
The youths had also thrown snooker balls and cues about.
No members of staff were injured, but a number of the youngsters suffered cuts and bruises, which the Home Office said were superficial and mostly self-inflicted.
The inmates, aged between 15 and 18, were moved out of the wing because the flood water had damaged the electrical system.
HM Prison Hindley, in the Bickershaw area, has three young adult wings and two youth wings.
The Prison Officers Association said staff concerns that the inmates would riot were ignored by managers.
Steve Gough, vice chairman of the association, said: "The staff work with the prisoners and they know each other intimately, and if the staff are telling you that there's going to be serious problems then virtually all the time there will be.
"Staff don't make these things up. The fact that management appear to have ignored that needs to be investigated."