Levels of violence and disorder have reduced significantly at Maghaberry Prison according to prison inspectors - however, they also found that more still needs to be done to help vulnerable prisoners.
The report was compiled jointly by Criminal Justice Inspection (CJI) and Her Majesty’s Inspector of Prisons in England and Wales.
In 2015, the same inspectors branded the Co Antrim prison "dangerous and Dickensian", but they have now said the prison has made immensely encouraging progress.
The high-security prison holds life prisoners convicted of the most serious offences including murder and paramilitaries.
Many struggle with substance abuse, self-harm, lack of education and poor mental health and some are extremely vulnerable.
The report also said: “Levels of violence and disorder had reduced significantly and the prison was much more stable and calm, while relations between staff and prisoners had been "transformed."
Areas where inmate congregate were once no-go zones for staff but are now regularly patrolled.
However, reservations remain over the handling of vulnerable prisoners.
Five inmates have killed themselves since the last inspection and the response to recommendations following deaths in custody was "insufficient", the report said.
A "very high" 500 reports of prisoners at risk had been opened recently.
Observation cells for inmates vulnerable to self-harm had been used 200 times and strip clothing, designed to be resistant to suicide bids, in 80% of cases, which inspectors noted can add to distress.
The unannounced inspection was conducted in April this year by Criminal Justice Inspection Northern Ireland, HM Inspectorate of Prisons, the Regulation and Quality Improvement Authority and the Education Training Inspectorate.
It said the regime inside was much better than observed previously and was being delivered reliably. It also said learning, skills and the provision of work had improved, but much more still needed to be done.
The report made 14 recommendations surrounding the negative perceptions held by many prisoners, the need for timely responses to health complaints, and poorer outcomes seen by Catholic inmates.