An examination of the records of all sick and violent men remanded to a large English prison suggested a tendency among police to consider men to be exceptionally dangerous simply because of their mental illness. On further study, however, there was no evidence that the mentally ill were more vulnerable to detention without subsequent conviction than their normal peers. Remand was rarely followed by help for the mentally abnormal men studied; this is disturbing as requests for psychiatric help constitute an important reason for custodial remand. Less than a third of the men with active symptoms went to hospital, although some of the less disturbed received supervision (including probation) orders, occasionally with treatment. As there is evidence that most of the few mentally abnormal offenders who subsequently receive treatment benefit from it, psychiatrists should do more for offender patients.