A riot broke out at a young offenders’ institute in Rochester, causing thousands of pounds of damage.
Teenage inmates at HM Cookham Wood sparked an all-day disturbance early on Wednesday morning.
It is believed trouble broke out among offenders, aged 16 to 18, in the education block of the unit, in Sir Evelyn Road.
According to a source, teenagers wrecked the area and caused thousands of pounds of damage.
Guards are understood not to have brought the situation under control until early evening.
Police were informed about the incident, but officers were not sent to the scene and the matter was dealt with by the Prison Service.
Medway Police said there may be police involvement later.
A Prison Service spokesman confirmed an “incident of concerted indiscipline involving five prisoners” took place.
He added: “The incident was resolved by staff and concluded at 7pm with no injuries to staff or prisoners.”