Prisoners in a notorious jail's ultra-high security wing have caused a violent disturbance, injuring four members of staff.
The incident at Belmarsh Prison was triggered when an inmate - believed to be a terror suspect - refused to hand over a laptop computer with which he was suspected of tampering.
The "jail within a jail" at Belmarsh, south-east London, holds some of Britain's highest-profile Islamist terrorists and terror suspects. Some inmates are allowed computers to work on their legal cases but are not allowed access to the internet.
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 incident was brought under control quickly."
She refused to say how many prisoners were involved, or at what time the incident took place. Four staff needed hospital treatment, she added.
It was reported last September that videos of hostages being beheaded were found on a laptop used by radical preacher Abu Hamza, who is detained at Belmarsh.
Judges sometimes direct that prisoners must have access to a computer because CPS paperwork is only available in DVD format.
Belmarsh Governor Claudia Sturt paid tribute to her officers' courage, saying: "Prison officers are in the frontline of protecting the public. This is yet another incident of ordinary people in prisons doing an extraordinary job, extraordinarily well.
"I am really proud of the bravery displayed by my staff, whose courageous response brought this incident to an end quickly."
