Inmates have spoken of their terror after hundreds of prisoners took over four wings at Birmingham prison, in what has been described as the worst disorder of its kind since the 1990 Strangeways riot in Manchester.
Two wings were sealed off after a disturbance broke out at about 9am, but G4S, which runs the prison, said it has now spread to another two wings. It has called in a specialist "Tornado" team plus dog units to contain the disorder.
The private security firm said the Prison Service had taken over the response due to the scale of the incident.
Speaking through his solicitor, one prisoner on the jail's G wing, known as the protected wing for inmates accused or convicted of sex offences, said: "We're terrified".
He added that other prisoners had been trying to get onto the wing and they feared they might be attacked.
The prison has been in lockdown all day, and specially-trained riot prison officers have been sent in to try to regain control of the jail, which is in the Winson Green area of the city.
As dusk fell, fires started to burn, and the sounds of men cheering, smashing, banging and firecrackers, could be heard from behind the high perimeter wall.
Meanwhile, there is a heavy police presence around the outside of the sprawling jail complex, which sits in the middle of a busy residential and industrial area.
The incident started in N and P wings, which normally house about 250 prisoners. The inmates at the heart of the disturbance have gained access to administration offices in those two wings.
After reports a member of staff had been assaulted, it is understood that all workers have been accounted for. Reports of fires inside the building could not be confirmed.
Paramedics were called to the prison shortly after 12.30pm but a West Midlands Ambulance Service spokesman could not give details of any patients or injuries.
Prison affairs academic and blogger Alex Cavendish claimed the disorder was "probably [the] most serious riot in a B category prison since Strangeways went up" in 1990.
He said an "inside informant" had told him the trouble started with lights being broken and inmates controlling fire hoses.
"The officers were then, as they are instructed to do, trying to get as many prisoners locked in their cells as possible to contain it," he said. "While one of the officers was putting a prisoner in the cell he was threatened with what appeared to be a used syringe."
Mr Cavendish explained that while this officer was distracted by the threat, "another inmate came up behind, snatched the keys from his belt and snapped the security chain".
Prisoners have also destroyed records held in an administration office, he claimed.
Most of the prison population was out on activities when the disturbance began and are now back in their cells.
A G4S spokesman said: "We continue to respond to an ongoing incident at HMP Birmingham which began just after 9am this morning. Our teams withdrew following a disturbance and sealed two wings, which include some administrative offices. The disturbance has since spread to two further wings.
He added that "all staff have been accounted for."
“Additional officers have arrived on site and we have deployed canine units within the prison. West Midlands Police helicopter is also in attendance," he said. “We are working with colleagues across the service to bring this disturbance to a safe conclusion.”
Shadow justice secretary Richard Burgon said the disturbances at the Birmingham jail are "hugely concerning".
"This is only the latest in a number of disturbances across the prison estate," the Labour MP said. "The Justice Secretary is failing to get this crisis under control."
West Midlands Police said its officers were stationed outside the prison, formerly called Winson Green, for reassurance purposes.
A witness who works near the prison said: "There's people in and out. All we see is fire engines, ambulances and police cars outside. There's a helicopter hovering above."
The Victorian prison was built in 1849 and houses nearly 1,500 inmates. It is also where alleged mass murderer Fred West hanged himself in 1995.
In July 2014 HMP Birmingham was found to be "making good progress" after being categorised as a failing prison "for many years" previously, according to HM Inspectorate of Prisons.
It was "calm and ordered" and "most prisoners generally felt safe". Inspectors added that "relationships between staff and prisoners were good and much improved from previous inspections".
Despite good work, however, the prevalence of illegal drugs "remained stubbornly high", they said.
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