Dartmoor Prison release of inmates 'rushed and poor'
Inspectors have identified "shocking" failings in work by HMP Dartmoor to protect the public from risks posed by men it releases.
A report by HM Inspectorate of Prisons (HMIP) found pre-release preparations for high-risk prisoners "was often unplanned, rushed and poor".
Of the 633 inmates at the Devon prison, 70% are sex offenders.
HM Prison and Probation Service said protecting the public is a priority and a review had taken place.
The number of sex offenders had doubled over four years as a proportion of Dartmoor's population to about 440 at the time of the August 2017 inspection.
HMP Dartmoor, one of Britain's oldest jails, releases "hundreds of men each year", the report said.
Peter Clarke, HM Chief Inspector of Prisons, said convicted sex offenders are not receiving support to reduce the "risks of harm" on release.
He said: "This was a shocking and totally unacceptable situation, given the generally high-risk population being released from Dartmoor."
Inspectors recorded that "too many sexual offenders were released without having sufficiently addressed their attitude, thinking or behaviour".
HMIP noted that the prison, built on land owned by the Duchy of Cornwall, remained under threat of closure and there was a "reluctance to invest in upgrading poor infrastructure".
Mr Clarke added: "While we considered Dartmoor to be well led and making strides in some important areas, it was being hampered by confusion nationally about its role, doubts about its future and inadequate resources to do the job it was being asked to do."
HM Prison & Probation Service said it prioritises public safety and a review of risk management arrangements had taken place.
It added that a new senior probation officer is already in post to oversee the management of higher risk offenders.