In a direct assault on the Probation Service, the Home Secretary will say that lax enforcement of community sentencing has actually added to the prison population, because it has encouraged offenders to continue their life of crime.
Mr Straw has chosen to send out his "get tough" message at the inaugural conference for Unlock, a new national association for ex-offenders, taking place in Rugby. He will tell delegates: "Most prisoners are sentenced to custody after receiving community sentences for earlier convictions. The level of the prison population in part reflects the failure of community sentences to reduce reoffending."
Mr Straw is particularly angry at the failure of probation officers to take action against offenders who consistently fail to turn up for community sentence appointments. Research has shown that 30 per cent of offenders repeatedly fail to attend, yet escape punishment.
Mr Straw has warned probation chiefs he wants such people brought back before the courts and sent to prison. A senior Home Office source said: "If community sentences are properly enforced, rather than being seen as a soft option, then a rise in prison numbers is a price worth paying."
Current community sentence initiatives include environmental projects, riding for the disabled and looking after war memorials. Mr Straw would like to see greater use of "focused" punishments such as drug treatment and testing orders and electronic tagging.
Probation officers argue that the present community sentencing regime is effective.
About 54 per cent of offenders on community schemes reoffend within two years, a similar rate to those sent to prison. Geoff Dobson, who chairs the Association of Chief Officers of Probation, said 125,000 offenders began such sentences last year, an increase of more than 5 per cent on 1997, which demonstrated the "confidence of the courts" in their effectiveness.
Another probation source said: "The public wants a probation service that is effective in dealing with offenders, not one that is gratuitously tough."Reuse content