Concerns over mental health issues, hygiene standards, and healthcare staff being ‘stretched to the limit’ at High Down prison have been raised by inspectors.

Issues surrounding the ‘unacceptably high’ level of prisoners-on-staff assaults and sex offenders not receiving rehabilitative interventions prior to release were presented by the Independent Monitoring Board (IMB) in April.

But a Prison Service spokesman said the Category B facility, in Highdown Lane, has seen a range of improvements since the report was published.

Among the main judgements in its executive summary, the report read: “The safety of the prison was compromised at times during 2017, in part due to there being insufficient or inexperienced staff to manage the daily challenges, and an increasing propensity for prisoners to resort to violence on each other, and increase of 43 for 2017.

“Although the assaults on staff decreased by ten for the same period, the board [IMB] is still of the opinion that this is unacceptably high.

“The board remains very concerned at the constantly high number of segregated prisoners that it believes reflects the volatile state of the prison.”

High Down became a reform prison last year, which provided benefits such as funding for equipment and the ability to ‘opt-out’ of the public sector recruitment process which enables ‘faster recruitment’, it continued.

Other improvements include the installation of cell window grilles for houseblocks in a bid to improve cleanliness around the prison’s outside areas, while the ‘Les Miserables’ production was seen as a ‘resounding success’ and boosted morale.

It added: “The board has been informed of the decision to re-role the prison to Category C during 2018 and has reservations on the decision being that the prison currently only has 417 work places and 184 educational places for an operational capacity of 1,160.

“In addition to this, the resettlement centre was closed for much of 2017. At present, sex offenders receive no rehabilitative interventions before release and the board understands that this will not change under the re-role.”

In response, a Prison Service spokesman said the recategorisation of High Down is ‘part of an ongoing process across the prison estate’ which is expected to be complete by the end of this year.

New initiatives to tackle drugs, violence and mental health concerns have been introduced since the report was published.

He added: “Further improvements must be made, which is why we are offering additional support for prisoners and implementing measures to reduce the amount of drugs entering the prison.”

According to the Ministry of Justice, High Down prison has new drug detection equipment in a bid to detect substances coming in through post, while working ‘even more closely’ with Surrey Police.

Prisoners are now being given more time out of their cells following a routine which was introduced in February, while figures for prisoner-on-staff violence have ‘decreased’ since the report came out.

A Category C prison remains closed and deems prisoners who cannot be trusted in open conditions but are also unlikely to escape.

This is a change from tighter measures to ensure prisoners cannot escape - in a Category B facility - but also do not require maximum security.

The IMB, a body which monitors prisoners’ welfare across the UK, inspected the prison from January to December last year before releasing its annual report last month.