Prison officers have warned that "roving riots" could spread through British jails after the third serious disturbance in less than a week.
Five hours of disorder were brought to an end early yesterday morning at Ranby prison at Retford, Nottinghamshire. More than 50 prisoners were involved.
The disturbance came a day after violence involving 26 inmates at Lindholme prison at Doncaster in South Yorkshire. Another serious incident involving six prisoners broke out at Guy's Marsh prison at Shaftesbury, Dorset, last Friday.
All the disturbances took place in low-security establishments and officers warned that overcrowding was leading to dangerous prisoners being housed in lax conditions. Brian Caton, of the Prison Officers' Association, said: "What we are seeing are roving riots. The problem is that category B prisoners are having to be held in category C conditions."