A report has criticised the treatment of vulnerable inmates at Maghaberry Prison in Co Antrim.
Chief Inspector Brendan McGuigan says the high-security jail poses the biggest risk in the north's criminal justice system.
A new report praises the efforts of its leaders, but says its most vulnerable inmates still are not getting the right care.
Northern Ireland's Prison Service says thatthe jail is making progress at rehabilitating inmates.
In his report, Chief Inspector Brendan McGuigan says more needs to be done, however.
"This one area is stubbornly refusing to show any improvement, and while that remains then vulnerable prisoners are really at risk," he said.