The Government has "serious concerns" over the performance of a private prison in the West Midlands, new documents have shown.
Out of 134 prisons in England and Wales, only three were rated "of serious concern" by the Ministry of Justice.
The private jail, HMP Oakwood in the West Midlands, operated by G4S, was one of them.
The poor ratings come just after G4S were criticised for overcharging the MoJ for electronic tagging of criminals, leading to a Government-wide review of all contracts held by the FTSE 100 giant.
The ratings prompted more calls for Justice Secretary Chris Grayling to reconsider his plans to privatise a large chunk of the Probation Service, under what he has dubbed a "rehabilitation revolution".