Concerns raised over spending on prisons

The cost of prison and probation in England and Wales jumped from 3.6bn in 2004-05 to 4.9bn in 2008-09, researchers found.

They said the mounting bill, which grew by more than a third (36 per cent), came despite a massive shake-up aimed at saving cash.

Dr Roger Grimshaw, of the Centre for Crime and Justice Studies at King's College London, questioned whether the spending could be sustained.

He said: "Prison and probation expenditure has increased dramatically over the past decade. Yet the frontline is running to catch up with demand.

"How sustainable or desirable is this spending in the age of austerity and how realistic are the current demands placed on the criminal justice system?"

The research is the latest contribution to the raging debate over a substantial shift in prison and probation policy.

The coalition Government pledged to shake-up the criminal justice system, focusing on rehabilitating criminals and reducing the number of prisoners. Ministers say they want private sector companies and charities to be paid by results as they divert offenders from a life of crime.

The prison and probation system, known as the National Offender Management Service, was pilloried as a failure since its creation in 2004.

Prison reformers and union staff labelled the service a "byword for waste, centralisation and bureaucracy" and repeatedly called for it to be broken up.

Earlier this week, outgoing chief inspector of prisons Dame Anne Owers said there was an "inflated prison system in a shrinking state".

The prison population reached 85,074 last month.