concerns have been raised at the way detainees are treated at an immigration removal centre.
An “excessively punitive” use of separation, poor level of activity, and inadequate preparation for release was found at Brook House, near Gatwick Airport.
However, substantial improvements were found following an earlier inspection in March 2010 where the centre was said to be struggling to meet basic standards of safety and decency.
The HM Inspectorate of Prisons report follows an inspection in September 2011.
Chief Inspector Nick Hardwick wrote: “Of significant concern was the excessive and often illegitimate use of the separation unit.
“The creation of a so-called enhanced wing was inappropriate in the context of a detainee population, and the application of a prison-style basic regime, which included separation within its sanctions, was excessively punitive.”
He continued: “At this unannounced follow-up inspection, we found substantial improvements. Detainees were safer, and staff were more skilled in their interactions with detainees and better supported by managers. The centre provided a more settled and respectful overall environment. However, significant concerns remained.”
Up to 426 male detainees can stay at Category B Prison Standard Brook House.
The average detention is three months, though a significant number stay for ten months or more.
One Zimbabwean had been held for four-and-half years, the report found.
A Gatwick Detainees Welfare Group spokesperson said: “We have long had concerns about people with serious mental health problems being held in isolation, and in poor conditions, apparently because their behaviour could not be managed on the main wings of the centre.
“Long-term detention is a primary concern for us, as we support many people who have been held for many months and even years in detention, with little chance of their removal happening in a reasonable period, as the law dictates.
“Brook House is, and will always be, an unsuitable place to hold people for any great length of time, as it was essentially designed to hold people for short periods only.”
Jerry Petherick, of G4S Care and Justice Services, which operates Brook House, said: “We have worked hard to improve the safety, security and well-being of detainees at Brook House, and we are pleased this report has recognised the ‘substantial improvements’ which have taken place since the last inspection.
“We recognise that challenges remain and we will be reviewing all the recommendations with a view to address outstanding issues.”