Criminals being supervised by the probation service have committed more than 1,100 serious offences over the past two years.
As well as one murder a week in England and Wales, official figures show that 1,167 serious further crimes were carried out by offenders who were under the care of probation officers.
The total for 2007-8 and 2008-9 included 94 murders, 105 rapes and 43 arson attacks. The Ministry of Justice statistics also revealed that another 657 criminals on probation were found guilty of serious violent or sexual crimes for which the maximum prison sentence is more than 10 years. More than 400 other criminals are accused of committing serious further offences but their cases have not yet come to trial.
The details were revealed in the 2008 Offender Management Caseload Statistics, which reveals details about the scale of the prison and probation workload.
Separate figures showed the prison population reached 83,900 at the end of June, up 4 four per cent on a year earlier and a rise of nearly 30 per cent over 10 years.
The Justice minister, Claire Ward, said: "The vast majority of serious further offences are committed by offenders given a community order by the court having been convicted of less serious offences. In most cases, nothing in their previous offending histories has indicated that they would be capable of such serious offences."
The serious further offences rate was about 0.3 per cent of all offences last year., she added.