Five prison staff were treated in hospital after a «major disturbance» at HMP Bedford, the Prison Officers’ Association (POA) has said.

It said «riot squads, with the support of dog sections and local staff, regained control» after violence broke out on Sunday morning.

The Ministry of Justice confirmed that «staff successfully resolved an incident» at the prison. However, it rejected the claim that «riot squads» were deployed.

The department said there was no threat to the wider public. It has not commented on whether prison staff were injured. However, prisons minister Rory Stewart said: «We do not tolerate violence against our staff — that’s why only this week we doubled sentences for those who assault them and why we will seek the prosecution of all those found to be involved in this incident.»

HMP Bedford is a Category B facility which holds more than 500 male prisoners.

Last week, the chief inspector of prisons triggered an «urgent notification» process at the prison after inspectors warned that inmates had effectively taken control of the facility.

In May the publicly-run prison was placed in special measures by the government because of safety concerns.

The POA said the disturbance demonstrated that «local governance has failed to protect POA members». In a joint statement the national chair, Mark Fairhurst, and general secretary, Steve Gillan, said: «The POA are appalled that members’ concerns and rights to work in a violence-free workplace have once again been ignored.» They said they «fully expected» Mr Stewart to insist that prison and probation (HMPPS) directors listened to the POA and «immediately act to address our members’ concerns».

The minister said nationally, 3,500 extra officers had been recruited and an extra £40m was being spent on safety, security and the fabric of the prison estate.»We need to reduce violence in our prisons — I am confident we will achieve that aim through taking this decisive action and working constructively with all parties moving forward,» he said.