Prison officers have begun protest action "until instructed otherwise", their union has said.
The Prison Officers' Association (POA) trade union said its general secretary Steve Gillan had called for all members in England and Wales prisons to take protest action outside their workplaces from 7am on Friday until instructed otherwise.
The POA said the action was in response to a report on Thursday by chief inspector of prisons Peter Clarke who raised the alarm over the potential for a "complete breakdown" in order and discipline at HMP Bedford.
Inmates have effectively taken control at the violent, overcrowded and vermin-infested jail, the watchdog said.
The POA said: "The unprecedented levels of violence and failure of this Government and employer to provide safe prisons has been headline news for some considerable time.
"The rise in violence against staff in prisons is laid firmly at the feet of Government and HMPPS (prisons and probation service), who have overseen the demise of the prison service over the last eight years."
Prisons minister Rory Stewart said: "Prison officers do vital and important work and we urge them to return to their duty stations, in line with their obligations to the law and the Prison Service.
"It's irresponsible for the POA to encourage their members to take this unlawful action. We are deploying our contingency plans but, by not turning up for work, these prison officers are putting their fellow staff and inmates at risk.
"Yesterday we doubled the prison sentence for anyone who assaults prison officers. We've also increased pay, provided tools such as body-worn cameras to increase security on the landings, and are investing £40 million to improve the estate and tackle the drugs problem which is fuelling much of the violence.
"And we've now got 3,500 new officers to help ease the burden.
"We are taking the action that needs to be taken."