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General Defences In Criminal Law Notes

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1. Defences are ways D can avoid criminal liability despite prima facie liability (AR + MR established). However, some things described often as defences are actually denials of the offence a. Scope i. General defences - available for any offence (e.g.
ii. Particular - limited to specific offence (e.g. loss of control is only for murder)
b. Type i. Complete - results in an acquittal (e.g. automatism)
ii. Partial - results in a reduction of liability (diminished responsibility reduces murder to manslaughter)

2. Classification of defences a. Defences based on finding that D acted in a permissible manner i. Private defence ii. Necessity iii. Chastisement iv. Consent b. Defences based on pressure exerted upon D by another i. Duress ii. Coercion iii. Entrapment iv. Superior orders c. Defences based on D's mental condition i. Automatism ii. Insanity iii. Diminished responsibility iv. Provocation v. Infancy vi. Intoxication vii. Mistake 1. INTRODUCTION: THE THEORY OF DEFENCES


LR 108


E XCUSES ' (1982) C RIM LR 732 [ LAW





1. Two different claims a. D was insane at the time s/he committed the offence b. D was insane at the time of trial and so unable effectively to defend him/herself

2. Requirements a. Basic definition - (McNaghten)
i. D must demonstrate s/he was suffering a defect of reason caused by a disease of the mind which meant that either -

1. s/he did not know the nature or quality of his/her actions, or

2. s/he did not know what s/he was doing was wrong b. Disease of the mind i. To be given its normal meaning (Kemp) - not a medical term; what must be shown is that D was suffering from a disease affecting mental function

1. No need to show it was a disease of the brain
a. E.g. diabetes can amount to a disease if it produces a malfunctioning of the brain

2. Malfunctioning of the brain may not necessarily mean disease a. E.g. if D was hit on the head by a brick and suffers concussion - there might be no disease. Similarly, being intoxicated cannot form the basis of an insanity defence, even if it causes a psychotic episode (Coley)
ii. Bratty - disease of the mind was a mental disorder which manifested itself in violence and was prone to reoccur, but these dicta have been rejected by
Sullivan - it is clear the disease **need not be prone to recur nor manifest itself in violence c. Defect of reason i. Must be shown that disease of the mind gave rise to defect of reason - D's power of reasoning must be impaired; not enough to show that it was available but not used (Sullivan)

1. Lord Diplock - impairment of faculties of reasoning, understanding or memory d. D did not know quality or nature of his/her act i. Requires proof that D did not know what s/he was doing. Examples -

1. D had no awareness of what was happening,
because of a seizure for instance (Sullivan)

2. D was aware of what s/he was doing, but deluded as to material circumstances of his/
her actions, rendering the act fundamentally different -
a. e.g. thought s/he was killing a monster when s/he was killing another person

3. D who was unaware of the consequences of his/her act, e.g. a person who cut off the head of someone who was asleep because 'it would be great fun to see him looking for it when he woke up'
a. Sets a fairly high threshold for mistake as to what the physical consequences of the act may be - not about moral quality/how people might feel in response to the act e. Not knowing the act is wrong i. 'Wrong' here means illegal (Windle), followed by
Johnson, which preferred illegality because what was or was not immoral was too uncertain

3. Insanity and strict liability a. Harper (1998) held that insanity was not a defence to a strict liability offence i. However, most commentators take the view that the decision is wrong

1. Made no reference to an earlier decision -
Hennessy, which stated insanity was a defence to strict liability offences

2. Reasoning is suspect - claimed that insanity was a denial of MR, but if that was all insanity was there would be no need to have it as a special defence, because any D would lack MR and prima facie liability

4. Burden of proof a. One of the two instances in criminal law where D has burden of proof to show he is insane on a balance of probabilities (Loake)

5. Insane at time of trial a. Key issue is whether D is able to understand the charge and the difference between guilty & not guilty pleas b. D's mental capabilities must be sufficient for him/her to be able to conduct his/her defence adequately i. Includes - to challenge jurors, to instruct counsel, and understand the evidence (Robertson)
c. Once it has been determined that D is unfit to stand trial,
judge has wide discretion as to appropriate course of action, except in the case of murder i. 1991 Act includes disposals ranging from absolute discharge to admission to hospital with a restraining order


SS .

4, 4A, 5

[5] - Powers to deal with persons not guilty by reason of insanity or unfit to plead etc.

1. This section applies where—
a. a special verdict is returned that the accused is not guilty by reason of insanity; or b. findings have been made that the accused is under a disability and that he did the act or made the omission charged against him.

2. *The court shall make in respect of the accused— a. a hospital order (with or without a restriction order);
b. a supervision order; or c. an order for his absolute discharge.

3. Where—
a. the offence to which the special verdict or the findings relate is an offence the sentence for which is fixed by law,
and b. the court have power to make a hospital order, the court shall make a hospital order with a restriction order
(whether or not they would have power to make a restriction order apart from this subsection).

"to establish a defence on the ground of insanity, it must be clearly proved that at the time of the committing of the act, the party accused was labouring under such a defect of reason, from disease of the mind, as not to 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."

K EMP [1957] 1 QB 399

1. Legal significance a. It does not matter whether the defect of reason is due to a degeneration of the brain or to some other form of mental derangement. The law merely considers the state of mind D was in, not how he got there b. **The hardening of the arteries led to a "disease of the mind" within M'Naghten Rules - does not have to be a disease of the brain

2. What happened a. D of previous good character made an entirely motiveless and irrational violent attack upon his wife with a hammer,
and was charged with causing GBH
b. He suffered from hardening of the arteries which lead to a congestion of blood in the brain. This caused a temporary lack of consciousness, so that he was not conscious that he picked up the hammer or that he was striking his wife with it. He sought to raise the defence of automatism c. Held - D was insane


V. B AXTER [1958] 1 QB 277

1. Legal significance

2. What happened a. D charged with dangerous driving. He claimed to have no memory from an early point in his journey to immediately after the incident, and contended that he had been overcome by a sudden illness and was therefore not liable under criminal law.

3. Reasoning a. Relevant offence contained an absolute prohibition and raised no question of MR. The key question was whether the defence of automatism applied. The onus of proving automatism rested with B given that it was a fact exclusively within his knowledge. The defence of automatism, in effect, says that D did not know or appreciate the nature or quality of his actions. In this sense, it gets very near to the defence of insanity.
There was no evidence in this case that B was suffering from a "black-out." His own evidence was consistent with falling asleep or not paying proper attention. Therefore, it was improper to find that B was not fully responsible in law and the appeal was allowed.




1. Legal significance a. Held that disease of the mind was a mental disorder which manifested itself in violence and was prone to reoccur i. Rejected by Sullivan

2. What happened a. D strangled and killed a young woman whilst giving her a lift, dumped her body on the side of the road and drove home b. D suffered from psychomotor epilepsy and stated that at the time of the killing a terrible feeling came over him and he was not conscious of his actions. He wished to raise the defence of automatism but the trial judge refused and instead directed the jury with regards to insanity, and D
appealed on this basis c. Held - trial judge direction was right - insanity, not automatism
Q UICK [1973] QB 910

1. Legal significance a. Fact pattern - hypoglycaemia and malfunctioning of D's mind was caused not by his diabetes but by the external factor of excessive consumption of insulin - hence not a disease which disturbed the working of his mind.

2. What happened a. D was a nurse who attacked one of his patients whilst on duty - charged with assault occasioning ABH under s.47
OAPA 1861 b. D sought to raise the defence of automatism as at the time of the attack he was hypoglycaemic, in that he had taken too much insulin and eaten very little on the day in question. In addition he had consumed alcohol before the attack. The trial judge ruled that this gave rise not to automatism but insanity c. D appealed d. Held - trial judge was wrong - not insanity but automatism
S ULLIVAN [1983] 2 A LL ER 673

1. Legal significance a. **Upheld McNaghten rules -
i. Jurors ought to be told in all cases every man is presumed to be sane, and possess a sufficient degree of reason to be responsible for crimes, until proven contrary to their satisfaction -
ii. D must demonstrate s/he was suffering a defect of reason caused by a disease of the mind which meant that either -

1. s/he did not know the nature or quality of his/her actions, or

2. s/he did not know what s/he was doing was wrong

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