1. Insanity

2. General
It is only the insanity at the time of the offence which matters, not insanity afterwards
(insanity afterwards may be relevant when deciding whether D should stand trial)
Burden and Standard of proof:
If D raises the defence - Burden on D. Standard – balance of probabilities
If prosecution raises the issue – Burden on P. Standard – beyond reasonable doubt

3. Elements of the Defence
M’Naghten – attempted assassination of the Prime Minister, Sir Robert Peel. D missed but killed Peel’s secretary, Edward Drummond. Medical opinion suggested D was mentally ill and HoL set out rules for use in such cases:
Everyone is to be presumed to be sane
Insanity may be proved if:
D suffered from defect of reason
Caused by a disease of the mind
D does not know the nature and quality of his act or does not know that what he was doing was wrong

4. Defect of Reason Defect of reason must be at the time of the offence
Inability to use powers of reason – not failing to use powers or reason
So not a person who is confused or absent-minded
Clarke – D charged with stealing from supermarket – transferred some items from basket to her own bag and left shop without paying. Claimed she must have done so in a moment of absent-mindedness. Held – being temporarily absent-minded does not mean she was deprived of reason – not insanity

5. Caused by a Disease of the Mind
Defect of reason must be caused by a disease of the mind
Legal term not a medical term
Must be a physical disease rather than brought about by external factors such as drugs:
If caused by internal factors – defence of insanity
If caused by external factors – defence of automatism
Can be temporary or permanent
Courts have attempted to define “disease of the mind” over many years but we really only have examples from cases of what has been classed as “disease of the mind”

6. Examples of “Disease of the Mind”
Kemp – D suffered from arteriosclerosis – affects the flow of blood to the brain. Sometimes caused a temporary lack of consciousness. During one such episode he attacked his wife with a hammer and killed her – court held disease of mind could be temporary
Bratty – D suffered from a psychomotor epileptic seizure while driving his van with a girl in the passenger seat. D took off her tights and strangled her with them. Held –any mental disorder that could lead to violence that was likely to reoccur is a disease of the mind
Sullivan – D kicked and injured his friendly elderly neighbour during a minor epileptic fit – held this could amount to insanity – shows how the legal and medical definition of disease of the mind are very different
Burgess – D was watching films with his friend at her flat when they both fell asleep. D hit his friend over the head with a bottle and a video recorder and then grabbed her throat. When she cried out he realised what he had done and claimed he had been sleepwalking. Held that sleepwalking caused by internal factor so disease of the mind - insanity

7. D does not know the nature and quality of his act OR does not know that what he was doing was wrong
“Nature and quality” refers to the physical quality of the act
D needs to prove any of the following:
He did not know what he was doing; or
He did not appreciate the consequences of his act; or
He did not appreciate the circumstances in which he was acting
Burgess – D did not know nature of act as he was sleepwalking
Sullivan – D did not understand what he was doing when he hit out during an epileptic fit
Kemp – did not understand the nature of what he was doing because of a lapse of consciousness

8. D does not know the nature and quality of his act OR does not know that what he was doing was wrong
Means D did not know what he was doing was legally wrong
If D did not know that what he was doing was wrong he has mens rea for the offence but because of insanity he does not know it was wrong so can use the defence
Windle – D killed his insane wife but pleaded his own insanity. He originally gave himself up to the police saying “I suppose I’ll hang for this”. As he showed he knew the nature and quality of his act, and that what he was doing was wrong - no defence
Johnson – D forced his way into neighbour’s flat and stabbed him with a large kitchen knife. D said he did not know what he was doing. Judge said he knew his actions were legally wrong so the defence failed

9. Insanity and Intoxication
If the defect of reason comes about through intoxication, the defence fails
Lipman – D had taken LSD and was hallucinating. Thought he was fighting snakes and killed his girlfriend by stuffing a sheet down her throat. Defence of insanity failed
If defect of reason results from alcoholism it could succeed as this can be classed as a “disease”

10. Consequence of the Defence
Successful defence – D found not guilty but given a special verdict of “not guilty by reason of insanity”.
Criminal Procedure (Insanity and Unfitness to Plead) Act 1991 – Court has range of options:
If murder – court must make hospital order restricting D’s discharge indefinitely
For any other offence:
Hospital order and an order restricting discharge either for a limited or unlimited period of time
Guardianship order
Supervision and treatment order
Order for absolute discharge

11. Why it is not a popular defence
Has a special verdict rather than acquittal
Was more popular when the death penalty was used for murder
Also, they now have the option of pleading partial defence of Voluntary Manslaughter Diminished Responsibility
Ds are not keen on the potential indeterminate orders that can be made
But if D raises evidence of his mental state by pleading diminished responsibility or automatism, prosecution can then raise insanity

12. Questions on Insanity Is there a defect of reason?
Is it caused by a disease of the mind? (remember it must be an internal factor for insanity)
Does one of the following apply?
D does not know the nature and quality of his act; or
He did not know what he was doing; or
He did not appreciate the consequences of his act; or
He did not appreciate the circumstances in which he was acting
D does not know that what he was doing was wrong