HMP The Mount: No charges over two-day prison riot

No prisoners will be prosecuted over a two-day riot in which armed inmates took over a wing and smashed windows, it has emerged.

Riot-trained officers were sent to HMP The Mount, Hertfordshire, after trouble broke out on 31 July and 1 August.

Hertfordshire Police said it had exhausted all lines of inquiry and no charges would be brought.

Prisoners "must not feel they can do anything" without legal recourse, the Prison Officers' Association said.

Police said reports were received on 31 July that prisoners had "threatened prison officers and caused damage to the prison" over a 10-hour period.

At the time, it was reported by BBC home affairs correspondent Danny Shaw that one wing and half of another were "lost".

Riot-trained staff with shields entered HMP The Mount during a 10-hour disturbance on Monday, 31 July

The following day it was reported to police that a prisoner had been assaulted by two inmates, while well-placed sources told the BBC armed prisoners had taken over the Nash wing of the prison.

A "nucleus of about 30 prisoners" was said to have been involved in the violence.

A Hertfordshire Police spokeswoman said the force would investigate any further information if it came to light.

Analysis: Danny Shaw, BBC home affairs correspondent

Obtaining evidence from a prison environment is not as straightforward as it seems.

In the absence of CCTV footage or body-worn cameras - which have yet to be rolled out to all jails - investigators have to rely on witnesses.

And when those witnesses are prisoners that becomes problematic.

Some may fear reprisals if they speak to police, others might give false evidence to implicate others.

It will be immensely disappointing to the prison authorities and staff that police were unable to bring anyone to justice for the trouble at The Mount, let alone have enough evidence to send a file to the Crown Prosecution Service (CPS).

The message that troublemakers can get away with it is not one the Prison Service wants prisoners to hear.

The Prison Officers Association said it was "disappointed" criminal proceedings were not being pursued.

"The incident resulted in significant damage to the prison and costs to the tax payer," a spokesman said.

"Prisons have CCTV in all accommodation areas and so we are surprised evidence is not available to assist the police."

HMP The Mount was designed as a category C training prison built on the site of a former RAF station on the outskirts of Bovingdon village, Hertfordshire

Prison facts: HMP The Mount

The Mount Prison opened in 1987 as a young offenders institution and now houses more than 1,000 prisoners.

It was designed as a category C training prison built on the site of a former RAF station on the outskirts of Bovingdon village, Hertfordshire.

The prison is described as a "hybrid training and resettlement prison" for inmates in the final six months of their sentences.

A report in 2016 by the Independent Monitoring Board (IMB) found "all the ingredients" were in place for The Mount to suffer disorder such as has been experienced in other prisons:

• Staff shortages,

• Readily available drugs

• Mounting violence

The CPS said it had not received a referral from police in relation to this matter.

The Ministry of Justice said it would not comment as it was a matter for the police.

The BBC also asked the Ministry of Justice in October for the cost of repairs to the prison but was told a final amount was not yet available.

This followed a previous Freedom of Information request for a report into the disturbance, which was refused.

A "tornado team" entered HMP The Mount to tackle to disturbances

On the second day of trouble at The Mount, about 30 inmates at Erlestoke prison in Wiltshire also became violent and four people were reported to have been taken to hospital.

In October, prison staff were attacked with pool balls at the high-security HMP Long Lartin in Worcestershire.

Police have previously brought charges against those in other prisons involved in disturbances. In September, six inmates were convicted for their part in a 15-hour riot at HMP Birmingham in December 2016.