HMP Bedford riot: Officers brought in to control 230 inmates
A riot at HMP Bedford saw prison officers from across the country brought in to control hundreds of inmates who had taken over two wings.
Scores of prisoners reportedly flooded on to the prison's gangways in chaotic scenes at about 17:00 GMT on Sunday.
Police and specially-trained officers were called to the Category B prison amid reports of loud bangs or explosions coming from inside.
The prison service said no staff were hurt, but two prisoners were treated.
However, their injuries were not thought to be serious.
The Prison Officers Association (POA) said about 230 inmates got out of their cells and seized keys, broke into medicine stores and started small fires.
Glyn Travis, a POA spokesman, said prison officers were brought in from across the country to deal with the situation, which is a common occurrence when dealing with disturbances.
However, he said the number of inmates involved was unusual.
"They'd taken control of two wings. The situation was dangerous and was sensitively and professionally managed to ensure no one was injured," he added.
The Prison Service said the situation was brought under control after an operation that lasted more than six hours.
A Prison Service spokesman said: "Specially trained prison officers and staff from the emergency services have successfully resolved an incident involving a number of prisoners at HMP Bedford.
"An investigation into this incident will take place. We are absolutely clear that prisoners who behave in this way will be punished and could spend significantly longer behind bars."
In a recent report on HMP Bedford, inmates claimed it was easier to get hold of drugs than clothes or bedding.
Steve Gillan, general secretary of the POA, said the incident at HMP Bedford involved "concerted ill-discipline".
He said some officers had retreated to a "safe place" and teams of riot-trained staff had been deployed.
Mobile phone footage apparently from inside the prison was posted online, revealing chaotic scenes, with scores of prisoners out of their cells and in the prison's gangways, shouting and bellowing.
One video showed what appeared to be paper and furniture strewn across an atrium floor, although the footage could not immediately be verified.
Drugs 'easy access'
In a report on Bedford Prison published in September, almost twice the number of prisoners said it was "easy" to access drugs, compared to a previous inspection in February 2014.
The number saying they had developed a drug problem while at the prison increased from 4% to 14%.
The BBC understands the process of "safe unlocking" of HMP Bedford inmates by prison officers had been a "bone of contention" for some time, according to the POA.
Initial reports suggested staff had refused to unlock prisoners as they had concerns about what could happen. Prison sources told the BBC they were overruled by managers.
Last week, Justice Secretary Liz Truss unveiled a White Paper detailing £1.3bn investment in new prisons over the next five years, and plans for 2,100 extra officers, drug tests and more autonomy for governors.