Standards at a new Midland prison run by controversial security firm G4S were condemned today in a damning inspection report.

An examination of HMP Oakwood, near Wolverhampton, revealed “clear evidence” of illicit drug and alcohol use and “passive and compliant” staff whose behaviour bordered on “collusion” with inmates.

Prisoners said they felt unsafe, self-harm levels were high and inspectors said the jail “urgently” needed to decide how to address the behaviour risks posed by its 300 sex offenders.

The Category C institution, which only opened in April last year, houses 1,558 inmates.

G4S has also suffered a string of problems at Birmingham Prison, which it also runs.

Inside HMP Oakwood
Inside HMP Oakwood

It was forced to spend £415,000 changing every lock in the jail after a set of keys disappeared soon after it took over the Winson Green facility in October, 2011.

Chief Inspector of Prisons Nick Hardwick said Oakwood urgently needed to improve, while one jail expert called it to be brought under Prison Service control.

Mr Hardwick said: “There is a lot to do before Oakwood is operating anywhere near effectively.”

And Mark Leech, editor of national prisons newspaper Converse, said: “Unless the prison is drastically improved immediately, it should be removed from the management of G4S and brought under the control of the public sector Prison Service.”

But G4S said improvements had already been made.

Jerry Petherick, managing director for G4S custodial and detention services, said: “The mobilisation of any prison is a complex and challenging operation but the size and scale of Oakwood – the largest prison in the country – made this even more acute.

“We have already taken steps to make improvements, appointing a dedicated taskforce to address problem areas, such as the prevalence of drugs, while providing additional funding where necessary.

“This is starting to yield results.”