Dozens of prisoners have been removed from a corrections facility in the south-east English town of Bedford, after an estimated 230 inmates were involved in a riot there.
The incident, which took place at about 5pm (local time), was finally brought under control after six hours when police wearing riot gear used stun grenades to restore order.
Two prisoners were hospitalised after sustaining injuries in the chaos, while three men have now been arrested in relation to the disturbance.
A spokesperson for HM Prison Bedford said an investigation will be launched into the rioting.
"We are absolutely clear that prisoners who behave in this way will be punished and could spend significantly longer behind bars," he said.
The incident comes after concerns were raised over how long inmates were being kept in their cells, and an inspection that showed the facility was 173 prisoners over capacity.