Thousands of convicted sex offenders are being released from prison without receiving the treatment they need to change their behaviour, inspectors have said.
A damning report said there was a scary and disturbing situation where work to reduce the risk posed by criminals after their release was not happening to any meaningful extent in many jails.
Fears that prison staff were being groomed or intimidated by gangs and high-risk sexual and violent offenders also meant greater supervision should be offered by managers, the joint report by the prisons and probation inspectorates said.
The report, which said opportunities to reform inmates were being missed, found there were no plans to deliver treatment programmes to one in three sex offenders who needed one.
Chief inspector of prisons Nick Hardwick said the report made for a "very disturbing read".
"What's happening on the ground now in terms of offender management is too poor in too many places and needs to be galvanised," he said.
"On the face of it, it is just really disturbing.
"Sex offenders are being released without adequate interventions to reduce the risk that they will reoffend.
"However you juggle the priorities, that ought to be somewhere near the top."
Justice Secretary Kenneth Clarke called for a rehabilitation revolution two years ago, saying that simply banging up offenders and warehousing them in overcrowded prisons was bad value for taxpayers.
Mr Hardwick said the management of offenders was missing in "far too many places".
Steve Woodgate, the lead inspector, added that risk assessments were "no where near good enough", with one in four prisoners not having had a sufficient assessment.
"One in four people in prison in this sample not having been assessed is a bit scary," he said, adding that reviews were done in less than half (42%) of cases.
They are "not being followed up, not being reviewed, nobody's really on the case", he added.