The Chief Inspector of Probation has warned that the probation service may struggle to cope with additional pressure created by the government's planned early prisoner release scheme.
Martin Jones said the system was already under unprecedented pressure and was managing around 258,000 cases, according to comments reported on Wednesday.
His warning comes as the government faces scrutiny over plans designed to ease overcrowding in prisons in England and Wales.
The issue has attracted particular attention over the potential eligibility of serious offenders. Prime Minister Andy Burnham has asked the Justice Secretary to look for additional prison capacity as the government seeks to exclude more serious offenders from early release.
Police leaders have also raised concerns over the potential release of two men convicted of the manslaughter of PC Andrew Harper.
Separately, probation staff represented by Napo voted overwhelmingly in favour of potential strike action over workloads. The union has warned that excessive caseloads can affect staff members' ability to protect the public.
The government is expected to continue reviewing the scheme ahead of further releases planned for the autumn.