Mobile phone footage of the riot has appeared across social media
The Prison Service in the UK is to launch an investigation after a "riot" broke out at HMP Bedford which reportedly saw up to 200 inmates go on the rampage.
Officers and ambulance crews were called to the category B prison in Bedford town centre at around 5pm on Sunday.
The operation lasted more than six hours before the situation was brought under control. 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."
Mobile phone footage from inside a prison - but which cannot be verified - was posted on social media. Videos showed chaotic scenes with scores of prisoners out of their cells and in the prison's gangways, shouting and bellowing.
Prisoners have filmed themselves rioting at HMP Bedford - officers regained control of the prison after 6 hours last night pic.twitter.com/Gh0wHXKHGx— BBC Breakfast (@BBCBreakfast) November 7, 2016
One video showed what appeared to be paper and furniture strewn across an atrium floor. There were also reports of loud bangs or explosions coming from inside the prison. There were no injuries to prison staff but two inmates were treated for injuries that were not thought to be serious.
HMP Bedford, which has been on its current site since 1801, currently holds around 500 inmates.