Britain's biggest private jail management company, G4S, has warned MPs that the heads of prisons are being "undermined" by government policy.

G4S say governors must have control of areas such as healthcare, education and training so that they are "responsible and accountable for everything that goes on within their prisons". The company is concerned that governors do not have powers to change these aspects, which are core as they can affect inmates' moods and rehabilitation.

A prison source added: "The concern is that more levers are being taken away from the person in charge."

The warning is made in a G4S submission to the Justice Committee. It says: "This [policy] is serving to undermine the ability of prison governors to govern effectively… Good governors should be allowed to govern."

A Ministry of Justice spokesman said its policy was the best way of "tackling our stubbornly high reoffending rates".