Rehabilitation work is "not good enough" and safety has "deteriorated" at a prison on the Isle of Wight, according to inspectors.
The Inspectorate of Prisons found violence had risen at HMP Isle of Wight - and around half of the inmates maintain their innocence. The majority of prisoners are behind bars for sex offences, serving long sentences for serious crimes.
Inspectors visited the prison in April and May where concerns were raised over prison safety.
Around 40% of the approx. 1,000 inmates held at the category B training prison are over 50 years old, with a "significant proportion" being elderly and sometimes frail.
Chief Inspector of Prisons Peter Clarke said: "The long-term, high-risk sex offender population presented significant challenges in rehabilitation and release planning. We found a very similar picture to the previous inspection. Fundamentally, some good work was undermined by a lack of up-to-date assessments of risk and need, high offender supervisor caseloads and a lack of contact between offender supervisors and prisoners."
He says it meant one-to-one motivational work needed, with a large number of inmates maintaining their innocence, "could not take place."
The report found more than half of the inmates said they felt unsafe in the prison, suggesting while violence was still not widespread, it had "risen significantly" since the previous inspection.
Phil Copple, HM Prison and Probation Service (HMPPS) Director General of Prisons, said: "We recognise that more work is needed to make the prison safer. Every prisoner now has a dedicated officer giving them personal support and, combined with working closer with probation and local authorities, we expect to see an improvement in arrangements to prepare prisoners for release."