London: Staff at Oakwood prison near Wolverhampton have `resolved` an overnight incident, the security firm that manages the facility said on Monday.
A G4S spokesman said: "This incident was resolved successfully at 2.10am.
"Police and internal investigations will now take place.
"It would be inappropriate to comment further until these have been completed."
British media said a "serious disturbance" had broken out at the prison, which was the scene of a number of rooftop protests last year.
The prison -- the largest in England and Wales, housing 1,600 inmates -- opened in April 2012 as a training prison next to the existing Featherstone and Brinsford prisons.
Following a surprise visit in October, prisons watchdog HMIP described inexperienced staff and high levels of violence and self-harm at the jail, branded "Jokewood" by prisoners.
The privately run prison houses category C male prisoners, who are defined as those who cannot be trusted in open conditions but are not considered capable of escape.
G4S, notorious for its inability to fulfil its Olympics security contract, has been under review by the government following revelations it overcharged for criminal-tagging contracts.
The government has since announced that electronic monitoring will handed to another firm on an interim basis at the end of the financial year.