500 more inmates at HMP Oakwood 'superjail'

The £160 million 'superjail' is already Britain's largest but the new intake will see the total number of prisoners it is able to hold rise from 1,600 to 2,106 from July.

Some single cells are being converted into double rooms as part of the move by the Ministry of Justice to find extra space for prisoners – boosting the numbers held at the Featherstone jail by 20 per cent.

South Staffordshire MP Gavin Williamson said he was not against the move but wanted reassurances that there would be safe staffing levels.

He said: "I do not have an issue with prisoner numbers going up within the current building.

"But I want proper reassurances that there will be sufficient numbers of prison officers and that they are trained to the right level before this happens.

"It is of vital importance that the prison officers are given the right level of support."

The 22-acre site was built in a way that would allow it to easily increase the number of prisoners it can hold.

A Ministry of Justice spokeswoman said: "We are committed to making best use of our prison estate, in order to properly rehabilitate offenders and maximise value for the taxpayer.

"That is why HMP Oakwood will soon accommodate additional prisoners to make use of vacant places.

"We will never compromise on the safety of our staff or prisoners and will take a carefully phased approach when moving prisoners around the estate."

Currently every prisoner has his own cell, with a toilet, shower, underfloor heating, and landline telephone. But that will change as part of this move.

In recent weeks extra beds have been moved into some cells.

The move is part of the Ministry of Justice's prison improvement scheme which is seeing £1.3 billion invested to replace ageing and ineffective jails.

When it opened three-and-half years ago, Oakwood was hailed as a trailblazer and a model for future prisons.

It also boasted being the country's cheapest prison, costing about £12,000 a prisoner a year rather than the £20,000 for the average category C jail.

But run by the scandal-hit global security firm G4S, it quickly suffered a series of scandals.

There was a damning report where prisoners said it was easier to get hold of drugs than soap, it earned the moniker 'Jokewood', and prisoners ran riot amid a mutiny after staff lost control of one of the wings in January 2014.

But recent inspections have said the jail is improving.