Four prison staff have been injured during an outbreak of violence at one of Britain's most secure facilities.
The prison holds some of Britain's most high-profile terrorist suspects
The incident at Belmarsh in south-east London was triggered by an inmate who refused to hand over a laptop computer, the Prison Service said.
The staff were treated in hospital for their injuries. Officials refused to say how many prisoners were involved or what time the incident happened.
Belmarsh holds some of Britain's most high-profile terrorist suspects.
A Prison Service spokeswoman said: "A prisoner was suspected of tampering with his Access To Justice laptop and refused to hand it over, punching a member of staff.
"An altercation ensued involving a member of staff and prisoners."
The spokesman said the incident was quickly brought under control.
She said some inmates are allowed computers to work on their legal cases but are denied internet access.
Judges sometimes direct that prisoners must have access to a computer because CPS paperwork is only available in DVD format.