LIVING conditions for the country's most dangerous prisoners requires improvement to prevent possible "psychological deterioration" of offenders, the prisons watchdog has said.

Full Sutton Prison, near York, is one of the institutions singled out in a report by Nick Hardwick, chief inspector at HM Inspectorate of Prisons (HMIP).

In a report into close supervision centres (CSC) - maximum-security units which hold about 60 of "the most dangerous men in the prison system" - Mr Hardwick said the restricted daily regimes of the offenders amounted to "prolonged solitary confinement" in some cases.

But he praised jail staff for their care of the men, which he described as "impressive", and added the system was "basically well run".

The report aimed to look at the CSC system across England and Wales and identify issues, including in management and care at the units.

Mr Hardwick found that at some units prisoners were being held for periods of up to several years and with little prospect of progression and reintegration back into the main prison, as well as restricted family contact.

He said: "Daily living conditions in the small units were cramped, particularly in Full Sutton, Manchester and Wakefield. One prisoner described the experience as being 'like a submarine' - which captured both the claustrophobic nature of the environment and the isolation in which prisoners lived.

"Prisoners had a very restricted view or outlook and some units had little natural light. While some units had made efforts to add interest to communal areas, others lacked character or colour. Exercise yards were austere cages."