The plea of insanity in criminal cases can be traced back at least to the Babylonian Code of
Hammurabi which dates from 1755-1759 BC. It is a complicated defence and its origins in
modern law lie with the ' M' Naghten Rules' of 1843 formulated by British judges as
a jury instruction in cases where a plea of insanity had been entered. Daniel M' Naghten
shot and killed one Edward Drummond believing him to be the British Prime Minister Sir Robert
Peel and was acquitted on the grounds of insanity and the M' Naghten Rules still exert
considerable influence over defences today. Clearly a plea of insanity in murder cases is of
critical importance when the death penalty is still applied and even today it may still be the
difference between a life sentence in a high-security prison or an indeterminate one in a
secure psychiatric hospital. Meanwhile 27 of the USA' s 50 states have retained or
readopted the death penalty and at least 54 other countries including China Russia India
Iran and Saudi Arabia also retain it. Naturally a criminal who was liable to swing for
murder could and sometimes did make every attempt to appear insane and this book examines
some of these cases as well as trials in which the accused was indeed judged to be insane. The
failure rate is high of seven American serial killers who deployed the defence in their trials
only two were successful ending their days in secure psychiatric facilities two were executed
and the other three either died or were killed while serving full-life sentences or are still
in gaol.
