Interim figures for rates of reoffending among short-sentenced male prisoners released from Peterborough Prison since the social impact bond was launched there suggest that reconviction rates have fallen despite a rise nationally.

The figures, published by the Ministry of Justice today, track the frequency of reconvictions over one year of the first 16 months of the first cohort of released prisoners.

According to Social Finance, architect of the social impact bond, the figures show that there has been a 12 per cent decline in the frequency of conviction events per 100 prisoners since 2008 in Peterborough, compared with an increase of 11 per cent nationally.

The results also suggest that the scheme’s intervention has successfully reversed a trend whereby since at least September 2005, rates of reoffending by short-sentenced prisoners released from HMP Peterborough tended to exceed the national average.

Social Finance said in a statement: “We cannot infer from the figures whether the pilot has been a success or whether an outcome payment will be triggered because the measurements used are distinct from those which will be used for the Peterborough social impact bond.” The Peterborough cohort will be compared by an independent assessor with a statistically compiled control group, it said.

However, it added that the progress of the scheme so far supported the case for the government’s probation reforms by highlighting how interventions among a group that previously received no statutory support could have a positive impact.

Frances Crook, CEO of the Howard League for Penal Reform, tweeted in response to the figures: "Reduced reoffending at Peterborough PbR cost lots of new money. Where is new money for Govt roll out of programme"