PROBATION workers have warned a shake-up of the service could lead to another case like Dano Sonnex - the notorious Deptford murderer left free to walk the streets.

The government's overhaul of offender rehabilitation will see services outsourced to the private sector on a "payments by results" basis, with the aim of around 65,000 offenders serving sentences of up to two years, receiving extended rehabilitation.

Justice Secretary Chris Grayling wants services for higher and lower risk offenders to be split up, while every offender leaving prison will serve a minimum of 12 months under supervision in the community.

But probation workers have warned that progress made since the Dano Sonnex case - where a lack of probation resources and the failure to properly classify his risk meant the 23-year-old was free to brutally murder two New Cross students in 2008 - could be lost.

Mike Guilfoyle from probation union NAPO said: "As a result of this change will Londoners feel safer or not? The weight of evidence from those who do the job is no. We believe the safety of the public will be compromised.

"The potential for another Sonnex, we believe, is likely to increase."

He pointed out that the change could lead to a lack of transparency, with information about performance difficult to obtain.

Mr Guilfoyle said: "A whole raft of people who probation had a public accountability for now will be farmed out to any number of organisations."

Probation officer Peter Halsall from Lewisham, also a NAPO member, said: "There's been a huge improvement since Sonnex. Why are you then taking it apart?

"Do you want to entrust the safety of the population to a company like G4S which can't actually organise security for the Olympics?"

He warned that dealing with offenders meant monitoring their risk, and that would be harder with different categories of risk allocated to different providers.

He said: "The more organisations there are, the easier it becomes for somebody to get missed.

"The transfer process is just going to lead to a huge raft of bureaucracy. When you get that then you're putting people at risk."