This report documents Amnesty International’s concerns that Special Security Units (SSUs), in which “exceptional escape risk” Category A prisoners are held, constitute cruel, inhuman or degrading treatment. The conditions in SSUs, including “small-group isolation”, the lack of adequate exercise, natural daylight, or adequate medical treatment, and certain security measures, have led to serious physical and psychological disorders in prisoners. Many aspects of the SSU regime violate international standards. Amnesty International is also concerned that the conditions within the SSUs may seriously impede remand prisoners’ right to a fair trial. In February 1997 there were approximately 25 prisoners held in SSUs. The report concludes with a number of recommendations to the government, including that it should publish and implement the recommendations of the government’s own inquiry carried out in 1996 by Sir Donald Acheson.