A Suffolk jail which holds some of the most serious offenders in the country has been praised by an independent watchdog for having the lowest levels of self-harm and violence among category C prisons.

An unannounced inspection into HMP Warren Hill, in Hollesley near Woodbridge, in November and December last year found an “unwavering focus on progression” and strong staff-prisoner relationships.

The category C men’s prison was graded as ‘good’ – the highest grade – for safety, respect and rehabilitation by HM Inspectorate of Prisons, and reasonably good for purposeful activity.

This was unchanged from the prison’s 2015 inspection.

Peter Clarke, HM chief inspector of prisons, said the jail was “unusual among category C closed prisons” in that it is entirely dedicated to delivering services to support long-term or complex prisoners towards progression into open conditions or release.

He said: “It holds some of the most serious offenders in the prison estate. While to a certain extent they have been ‘selected’ for the unique regime the prison offers, we should not underestimate the risk they pose or the achievements of the prison in managing their behaviour.

“This is one of very few establishments that has such an unwavering focus on progression and on offering prisoners the opportunity to demonstrate, when being considered for re-categorisation, parole or release, how they have reduced the risk that they pose.”

MORE: Prison praised for ‘culture of hope’The report found Warren Hill, which holds around 240 prisoners, had the lowest incidence of self-harm and violent incidents among category C prisons with a range of “impressive” activities.

The one key concern for inspectors focused on expanding and improving the education provision, and ensuring that attendance was encouraged on a consistent basis.

Inspectors recommended using the internet and video on social media to enable prisoners to contact their families.

Mr Clarke said: “We are well aware of the potential risks associated with this, but would encourage Her Majesty’s Prison and Probation Service (HMPPS) to think innovatively as to how these risks could be managed and trials conducted in appropriate circumstances.

“It is surely inevitable that at some point in the future this will be seen as an entirely normal feature of prison life, and Warren Hill could well be the type of environment in which the possibilities and benefits could be usefully explored.”

He added: “Warren Hill was an excellent facility that benefited from dedicated staff delivering a range of specialist interventions in an atmosphere that encouraged good behaviour.

“It offered prisoners serving long sentences, many of whom have had little hope of progressing in the past, the chance to begin the often long and difficult path towards release or being placed in open conditions.

“We commend the approach and achievements at Warren Hill, and hope that the approach that is taken there to underpin effective rehabilitation can be used as an example for other establishments to follow.”

Phil Copple, HM Prison and Probation Service (HMPPS) director general of prisons, said: “The governor and staff should be extremely proud of making this the safest category C prison in the country.

“We are very grateful for all of their hard work. The prison has low levels of self-harm and violence, while relationships with prisoners are strong - giving them the best possible chance of turning their lives around.”