A policy of “preventive detention” has recently been debated in the British Parliament. Alarmed by the high-profile criminal activities of people suspected of having dangerous severe personality disorder , the government have made clear their intention to “indeterminately but reviewably detain” people with DSPD, after diagnosis by forensic psychiatrists, even if the individuals are yet to commit an offence. Such a policy may improve the safety of the public, but has obvious implications for civil liberties. This essay criticises the morality (...) of the government's intention and rejects the notion that the medical profession could ethically collude with such a policy. (shrink)