AbstractThis article describes the events leading to the introduction of the control unit in Wakefield Prison in 1974, and the way the unit operated. The control unit was recently the subject of litigation in the High Court, when a former inmate of the unit, Michael Sidney Williams, sued the Home Office for false imprisonment, claiming exemplary damages for oppressive and arbitrary governmental action and a declaration that the Home Office had no power to set up the unit. The article examines the decision and some of the possible implications for the future relationship between courts of law and prison administration.