All referrals to medical officers in Brixton Prison over a five-month period in 1989 were examined. This paper reports the progress through this remand prison of those men who were considered to be suffering from a major psychiatric disorder. Many men had been charged with relatively minor offences. The net effect of medical intervention was to delay release from custody. Because of the administrative delays inherent in the system of medical referral and hospital admission under section 37 of the Mental Health Act 1983, it was those prisoners who were most ill who tended to remain in prison for the longest periods. Judged in terms of its efficiency to ensure speedy treatment for mentally ill remanded offenders, the present system is regarded as cumbersome and extremely inefficient. It is suggested that greater use should be made of section 48 of the 1983 Act to divert mentally ill, remanded offenders from prison.