Chapter 4 further considers the ways in which prison medical officers provided evidence in court that might conflict with that of other medical witnesses and debated the applicability of the terms ‘criminal lunatic’, and ‘lunatic criminal’. The chapter discusses the establishment of institutional facilities for criminal lunatics, including Dundrum and Broadmoor, and legislative changes designed to establish whether individuals were ‘mad’ or ‘bad’. Prison medical officers now dealt with increasing numbers of cases of mental disorder among prisoners missed at the time of their trial or who became ill in prison. Though reluctant to relinquish prisoners and move them to asylums, many prisoners were transferred out of convict and local prisons and into criminal, district and county asylums, in a process often triggered by violence or disruptive behaviour rather than psychiatric diagnoses. The chapter explores how such transfers, and delays in making them, might trigger tensions between prison medical officers and asylum doctors and prison commissioners and lunacy commissioners and inspectors, evidenced in well-documented cases.