Specialist officers have been deployed to a disturbance involving inmates at a Hertfordshire Prison.
Prison officers lost control of the prison as serious disturbances broke out among the inmates.
The Ministry of Justice confirmed staff were working to resolve an incident within the prison.
Tornado Teams – elite officers trained to bring riots under control – are understood to have been sent in to deal with the incident.
The MoJ said the prison remained “completely secure”.
A prison service spokesperson said: “Specially trained staff are working to resolve an incident involving a number of prisoners at HMP The Mount.
“The prison is completely secure and there is no risk to the public.”
The Mount is a Category C prison in Bovingdon which holds more than 1,000 inmates.
The prison is known as a hybrid training and resettlement prison with its prisoners within the last six months of their sentences who are residents of Hertfordshire and surrounding areas”.