The Prison Officers Association (POA) has said its members "no longer feel they have control" over prisons after an officer was stabbed at a jail.
A series of what are believed to be racially motivated fights broke out in the exercise yard at HMP Risley near Warrington in Cheshire.
A guard tried to calm the disturbance on Thursday night but was stabbed.
The POA said: "The service undertakes an extremely dangerous job. Something needs to be done to put this right."
Colin Moses, National Chairman of the POA, said: "It is clear that officers and other uniformed staff no longer feel they have full control of prisons and prisoners.
Well what a surprise!!! BBC News Report