Inmates moved after prison riots
More than 250 prisoners have been moved to other jails after three consecutive nights of rioting, the Prison Service said.
The disturbances spread to an adult unit at Moorland prison after two nights of riots at the young offenders institution on the same site near Doncaster, South Yorkshire.
Prison Service chief executive Michael Spurr said additional staff were being sent to the prison "to ensure stability" as a high-level review was under way.
One prisoner was taken to hospital after being seriously injured during almost seven hours of trouble last night.
Up to 100 adult prisoners started throwing objects and causing damage on the wing at about 6.30pm on Thursday night.
Officers in riot gear, known as Tornado response teams, were called in and all prisoners surrendered, the Prison Service said.
Mr Spurr added: "We are now conducting a high-level investigation into these events. Staff have done a magnificent job over the past 72 hours. We have deployed additional staff today to Moorland to ensure stability at the prison. We have a good record of maintaining order and security in our prisons and are therefore taking these incidents extremely seriously in order to learn lessons."
A total of 166 prisoners were being transferred from Moorland to other prisons across the country, in addition to the 86 who were moved on Thursday after Wednesday night's riot.
Glyn Travis, a spokesman for the Prison Officers Association, said that all the prisoners in Moorland's adult wing, up to 100 inmates, were involved in the riot.
He confirmed that no prison staff were injured, but said extensive damage was caused.