Prison does not work, according to official figures to be released this week showing criminals are much more likely to commit further offences if they are sent to jail.
New Home Office research – which flies in the face of the Government's crime-fighting strategy – shows that community-based sentences, such as graffiti cleaning, litter collecting, graveyard repairs and anger management courses, cut reoffending more effectively.
Figures to be released to Parliament by the Home Office minister Hilary Benn will show that 44 per cent of criminals who are given community penalties are reconvicted within two years, compared with 56 per cent of those sent to jail.
News of the findings led last night to calls for thousands of prisoners to be released from jails on electronic tags and transferred to more effective punishments.
The research comes as the Government prepares the prison system to accept tens of thousands more offenders. The jail population is expected to rise from 72,000 to 110,000 in 2009. But the increased use of prison will increase levels of crime in the long term and waste millions of pounds of public funds, claim the research authors.
In a written parliamentary answer to Simon Hughes, the Liberal Democrats' home affairs spokesman, Mr Benn said the Home Office had re-evaluated community punishments. New "adjusted" figures show a wide gulf has emerged between the reconviction rates of those completing jail sentences in 1999 (55.7 per cent) and those given non-custodial punishments (44.3 per cent).
Previous research had shown there was little difference in the effectiveness of the two approaches.
Information provided by the Home Office to the House of Commons in 2000 stated that between 1987-1996 there was never more than 3 per cent difference in the reconviction rates for the two approaches and that, at times, prison had been judged to be more effective in tackling recidivism. It stated categorically: "There is little difference between the reconviction rate for custody and all community penalties."
Mr Hughes urged the Government to reconsider its position in the light of the latest research. "These figures put clear blue water between the custody and community options," he said.
"This should be the signal for a major shift of funding from prisons to probation. There are thousands of prisoners who could be out on a tag, under supervision, paying back to the communities they took from."
Harry Fletcher, assistant general secretary of the probation union Napo, said the Government had failed properly to resource frontline probation staff. He said: "It flies in the face of economic sense. Probation is one-tenth of the cost of prison and we now know it is more effective in reducing offending."
Deborah Clothier, chief executive of the Restorative Justice Consortium, said the Government needed to provide more information about the benefits of community penalties so that they would be more popular with sentencers. "People generally don't know about them," she said.
The Home Secretary, David Blunkett, and the Lord Chief Justice, Lord Woolf, have both spoken recently of the need to reduce the prison population. But penal reformers claim judges and magistrates have been afraid to use non-custodial sentences.