Discuss the defence of automatism
Automatism can be a defence in relation to all offences. Two elements are required: that the act is involuntary and caused by an external factor.
If defendant successfully argues automatism he is found not liable and acquitted.
Defendant must have acted involuntarily. Lord Denning noted
.. no act is punishable if it is done involuntarily … and involuntary is defined as the mind not controlling limbs in a purposeful way (Bratty (1963)).
Partial control can undermine automatism defence (Attorney General’s Reference (No. 2 of 1992)).
Involuntary act must be caused by an external factor not internal, such as disease (Quick (1973)).
General principle is that internal factors lead to insanity and external factors to automatism.
A defendant was driving a stolen car while disqualified. He was diabetic and not taken his insulin for four days. Defendant argued he was suffering from hyperglycaemia, which can lead to unconscious actions. Court found hyperglycaemia was caused by an internal factor, diabetes, so automatism not available, but insanity was (Hennessey (1989)).