Inmates have effectively taken control of a violent and vermin-infested prison, a watchdog warned.
Inspectors who ignored HMP Bedford inmates regular rules, found the smell of drugs "flooding" some wings and an infestation of rats.
The Chief Inspector of Prisons has issued an "urgent notification" in prison.
Minister of Prisons Rory Stewart said it was "clear that further action is needed".
Peter Clarke, Chief Inspector of Prisons, has sent a letter to Attorney General David Gauke, which means that the government must publish a response and action plan for the prison within 28 days.
In May, the government-run prison was classified by the government as a special measure because of security concerns.
It is the fourth prison to be subjected to the "urgency procedure" after Nottingham, Exeter and Birmingham.
Mr. Clarke said of HMP Bedford: "There was a dangerous lack of control in many parts of the prison, which led us to fear that it could all too easily lead to a complete collapse of order and discipline.
"Sometimes it felt like the prisoners were in control of when and if they would follow orders and agree with the authority."
The inspection, which was completed last week, found that the number of attacks on staff is higher than in other prisons in England and Wales (116 in the last six months).
It also turned out that one in five prisoners had admitted since he entered the prison to get drugs.
Living conditions were found to be poor and overcrowded while inmates lacked targeted activities.
The Category B prison accommodates more than 500 male prisoners, although the planned capacity is around 320.
Mr. Stewart said, "Bedford Prison faces great challenges, and we have put it in special measures before the inspection starts and bring experienced senior managers with us.
"Our focus will be on reducing violence and drugs and helping our prison officials bring Bedford around, and it's clear that further action is needed."