A former top Home Office civil servant says the government's offender management strategy will not cut crime.
Noms aims to improve the probation and prison services
Carol Hedderman said the new National Offender Management Service (Noms) will "never have much impact" on crime, while clear-up rates remain low.
Her article in a new book claims the increased use of imprisonment is not an effective way to reduce offending.
The Home Office said it was "confident" a new five-year plan would see a "real reduction" in re-offending by 2010.
The office says it is about to launch this plan.
The creation of Noms was announced in January 2004, when the government set out its plans for transforming the management of offenders.
Professor Hedderman, who worked at the Home Office for 13 years, said Noms will only work if problems cause by overstretched resources are tackled.
Prof Hedderman was deputy head of Home Office research and development until 2004. She specialised in probation and prisons, the two areas ministers are trying to improve under the new Noms organisation.
The professor, who is now based at the University of Leicester, called for Noms to be "radically repositioned".