A prison holding Gary Glitter and hundreds of other sex offenders is failing to challenge their criminal behaviour, a watchdog warned.

Chief inspector of prisons Charlie Taylor said there were “worrying weaknesses” at HMP The Verne, which was not running any offender behaviour programmes.

A “seriously understaffed and stretched” team of staff also meant high-risk inmates could spend years behind bars without “any challenge” towards their “dangerous” conduct, a report published on Monday said.

Some officers even said they did not want to know what crimes inmates had committed because they “felt it might prejudice their response”.

This meant some staff at the low-security jail in Dorset were “not aware what offence mirroring behaviour might have been manifested by prisoners” so could not fully contribute to parole hearings, according to the findings.

Glitter, whose real name is Paul Gadd, is among more than 600 sex offenders serving time at the 19th century former citadel in Portland.

Earlier this year, the 80-year-old was ordered to pay more than half a million pounds in damages after being sued by one of his victims.

The High Court heard he was sent back to The Verne after losing his latest parole bid for freedom, having temporarily been moved to another prison.

The disgraced paedophile pop singer was jailed for 16 years in 2015 for sexually abusing three schoolgirls between 1975 and 1980, But he was released in 2023 – only to be back behind bars less than six weeks after walking free when police monitoring revealed he had breached his licence conditions by reportedly trying to access the dark web and viewing downloaded images of children.

Although his sentence expires in February 2031 – by which time he could be aged 86 – a former head of Scotland Yard’s Paedophile Unit previously suggested he will likely die in prison after being re-called.

Mike Hames said the 1970s glam rock star would always represent a danger to children and taking him back into custody was appropriate.

Setting out the findings of an inspection in July, in his report Mr Taylor said: “Although HMP The Verne was a generally safe and respectful jail, this report also reveals some worrying weaknesses in addressing the offending behaviour of many prisoners.

“With no offending behaviour programmes on offer (although we have been subsequently told these will now be funded) and a seriously understaffed and stretched offender management unit, it was possible for high-risk prisoners to spend years at the jail without any challenge or support towards changing their thinking or dangerous behaviour.

“It was concerning that despite having a relatively settled staff team, only 2% had completed the HM Prison and Probation Service online training for working with prisoners convicted of sexual offences (PCoSOs) in the past year.

“Officers also told inspectors that they did not want to know what offences individuals had committed because they felt it might prejudice their response.

“As a result, they were not aware what offence mirroring behaviour might have been manifested by prisoners and they were unable to contribute more sophisticated analysis to prisoner offender managers before parole hearings.”

As a category C training prison, the focus of The Verne “should be providing prisoners with the skills and insight to avoid re-offending and settle successfully on release”, he said.

While Mr Taylor said the announcement during the inspection that “funding had been found to run offending behaviour programmes at the prison should be a spur to leaders to reinvigorate it, train staff, and do much more to address prisoners’ offending behaviour”, he added that the “fact that this money has taken so long to materialise from the prison service, while funding was provided for a substance free living unit, despite few prisoners having drug problems, was a questionable use of resources.”

A Ministry of Justice spokesman said: “The new Government inherited prisons in crisis and took immediate action to ensure we can lock up dangerous offenders, protect the public and make prisons safer for hard-working staff.

“Since this inspection, HMP The Verne has taken action to address the concerns raised, including extra training for staff and improved access to work and education opportunities for prisoners.”