In the latest blow to public confidence in the criminal justice system, a report seen by the Yorkshire Post reveals that just 32 per cent of criminals responsible for violent offences – categorised as everything from murder to assault to obstructing a police officer – are sent to prison.

But custodial sentences are handed down to more than 36 per cent of offenders convicted of non-violent offences, such as fraud, theft, burglary, criminal damage, drink-driving and public order offences.

The Home Office study on sentencing and re-offending was met with incredulity and outrage last night by Shadow Home Secretary David Davis and other MPs – but Prisons Minister Gerry Sutcliffe insisted the Government had been calling on the independent judiciary to be tougher with dangerous violent offenders.

In addition to the sentencing of violent offenders, the report revealed that a widely used alternative punishment to custody, the drug treatment order, has a re-offending rate of 82 per cent.

Another section appeared to contradict Ministers' claims about the dubious long-term effectiveness of prison by stating that "longer custodial sentences are associated with lower proven re-offending rates".

The conclusions emerged yesterday as the Home Office's latest British Crime Survey found public confidence in Britain's criminal justice system was falling.

The survey, which questioned tens of thousands of people during 2006 about their experiences of crime, showed that just 42 per cent of people had confidence in the system's ability to bring criminals to justice, down two points from 2005.

Only 37 per cent of people believed the system was effective at reducing crime, while 34 per cent thought it met the needs of victims of crime. Both were one point lower than the 2005 responses.

The Home Office "statistical bulletin" on offending, stated: "Violent offenders are less likely to receive a custodial sentence than other offenders."

But it sought to lessen the impact of the statement by adding: "'Violence' incorporates a wide range of offences of varying severity."

It noted the two most frequent violent offences were common assault and battery, and assault causing actual bodily harm.

On drug treatment orders, the report said they "had the highest actual proven re-offending rate" of any form of punishment in 2004.

On the link between the length of custodial sentences and re-offending, the data showed that the longer the sentence, the lower the rate of repeat offending.

It also revealed a rise between 2000 and 2004 in re-offending by people imprisoned for less than a year.

David Davis, the Tory MP for Haltemprice and Howden, said: "It beggars belief that under this Government, violent offenders are actually less likely to receive a custodial sentence than other offenders.

"It is precisely these types of serious offenders, representing the greatest risk to the public, who should receive a custodial sentence to protect the public."

Shipley Tory MP Philip Davies, who led a Parliamentary debate earlier this month calling for more and longer custodial sentences, said people would be "astonished" by the report's revelations.

He said: "The fact is that the system is soft on violent crime, that drug orders don't work and that, contrary to what the liberal do-gooders say, prison works."

Defending the Home Office, Prison Minister Mr Sutcliffe, the Bradford West MP, told the Yorkshire Post: "We've introduced harsher sentences and made sure there are places in prison for dangerous and violent people, who should be treated more severely. But sentences are for the judges to decide, not for politicians."

On drug treatment orders and the effectiveness of prison, he added: "Drug-related offenders are harder to deal with and we recognise they are a problem which is why we've increased funding for drug treatment by 974 per cent since 1997.

"But we've got to remember that not everyone should go to prison. We need to tackle and break the re-offending process by offering people a holistic solution involving education and jobs."