(iii) as to not know the nature and quality of the act he was doing or, if he did know it, that he did not know he was doing what was wrong. If the accused was conscious that the act was one that he ought not to do, and if the act was at the same time contrary to the law of the land, he is punishable.
- A person under a partial delusion is to be considered as if the facts with respect to which the delusion exists were real.
Daniel M'Naghten himself was tried and acquitted on the grounds of insanity and committed to Bethlehem Hospital. It is extremely interesting that if M'Naghten himself were tried according to the M'Naghten Rules, he would not have been found not guilty by reason of insanity - he would have in fact been found guilty and convicted!
In R. v Kemp (Albert) [1957] 1 Q.B. 399, an elderly man struck his wife with a hammer whilst in a temporary state of blood restriction to the brain due to a condition called arteriosclerosis and was found guilty but insane: Devlin J summing up: -
‘Hardening of the arteries is a disease which is shown on the evidence to be capable of affecting the mind in such a way as to cause a defect, temporarily or permanently, of its reasoning, understanding and so on, and so is in my judgment a disease of the mind which comes within the meaning of the [M’Naghten] Rules.’
In R. v Hennessy (Andrew Michael)[1989] 2 All E.R. 9, the appeal held the ruling of the trial judge in that, between whether Hennessy’s diabetic hyperglycaemia was a case of automatism or whether it was a case of legal "insanity" within the McNaghten Rules, it was concluded that it was the latter. Similarly, in Burgess, the Lord Chief Justice ruled that sleepwalking is an abnormality of the brain function so as to be regarded as a pathological condition and is therefore defined as a ‘disease of the mind’ within the principles of the M’Naghten Rules. The decisions in Kemp, R. v Sullivan (Patrick Joseph) [1984] A.C. 156 and Hennessy were upheld in Burgess, which determined that any pathological condition with an internal origin is a ‘disease of the mind’.
The insanity defence by way of the M'Naghten Rules is stigmatised – if rules existed that were more conducive with current notions of mental disorder, perhaps those people who do genuinely suffer with such illnesses would be tried accordingly. The unpopularity of the Rules appeared to exist mainly because under the Criminal Procedure (Insanity and Unfitness to Plead) Act 1964 (i.e. pre-1991), any person who was found not guilty by reason of insanity was sent to hospital for an indeterminate and indefinite period of time. Post-1991, Parliament decided that in cases other than murder, the ‘special verdict’ would lead to non-punitive sentences and an acquittal. Article 5 of the European Convention of Human Rights however justifies the detention of a defendant only if the unsoundness of mind were to continue.
In Reforming the Law of Unfitness to Plead and the Defence of Insanity Professor Ronnie MacKay states that there are not many people - lawyers, psychiatrists who would support the test in the M’Naghten Rules. In fact, Professor MacKay goes on to state that the Rules: -
‘are extremely narrow, they are cognitively based, it is all about what the accused knows or knew. Quite clearly it does not take account of volitional impairment of any sort... Although they are narrow, nonetheless the ‘disease of the mind’ component has been interpreted by the English Courts to include conditions such as sleepwalking, diabetes, epilepsy. In my view that presents a problem in respect of Convention compliance.’
Reconciling the M’Naghten Rules with the European Convention of Human Rights is evidently not possible – if a defendant commits a crime whilst sleepwalking (as in Burgess) for example, the precedence of the M’Naghten Rules would ensure that because the defendant suffers with sleepwalking, which is termed as a ‘disease of mind’ and a continuing illness, he or she would be found not guilty by reason of insanity and, in accordance with Article 5, be detained for an indeterminate period of time. This is clearly erroneous and proof that the ‘disease of mind’ component is not Convention compliant.
In conclusion, it does appear that the M’Naghten Rules need adapting to the modern notions of mental disorder. Insanity is a legal theory, not a medical concept and the Rules tend to create more problems due to the ambiguous and inconclusive wording than performing a helpful tool in the English legal system. Reform is being considered - The Butler Committee on Mentally Disordered Offenders
recommended the verdict of ‘not guilty on evidence of mental disorder’ (paras 18.14-18.36) instead of the current wording of the ‘special verdict’ - although this is yet to be implemented. It does seem clear that the insanity defence is virtually impossible to maintain according to the M’Naghten Rules.
