There has been a dramatic increase in violence at Erlestoke prison with the number of violent incidents going up from 800 to more than 1,400.
Inmates were thought to be a minimal threat at Erlestoke prison
The Devizes jail houses inmates thought to be a minimal threat, but a new report says much behaviour is more like that of a high-security prison.
The investigation by the Independent Prison Monitoring Board also reveals details of an attempted escape.
Instances of restraint having to be used on inmates have also risen.
Over the past year they went up to 23, compared to 13 occasions in 2003 and just six in 2002.
The report also shows there was one attempted escape in April last year when four prisoners tried to scale the prison security using contractors' scaffolding.
They were picked up by CCTV and brought back by staff.
A Home Office spokesman said: "Any use of force or assault on prisoner or staff is recorded as an incident and monitored.
"We believe that a significant reason for the increase is due to improved reporting by staff. Changes in population could also be a contributing factor.
It is worth noting that in the last year 1,400 incidents involving a form of violence were reported at the establishment yet only 23 of these required use of force by a member of staff."