General Defences

overview

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

   1. Scope

      1. General defences – available for any offence (e.g. insanity)

      2. Particular – limited to specific offence (e.g. loss of control is only for murder)

   2. Type

      1. Complete – results in an acquittal (e.g. automatism)

      2. Partial – results in a reduction of liability (diminished responsibility reduces murder to manslaughter)

2. Classification of defences

   1. Defences based on finding that D acted in a permissible manner

      1. Private defence

      2. Necessity

      3. Chastisement

      4. Consent

   2. Defences based on pressure exerted upon D by another

      1. Duress

      2. Coercion

      3. Entrapment

      4. Superior orders

   3. Defences based on D’s mental condition

      1. Automatism

      2. Insanity

      3. Diminished responsibility

      4. Provocation

      5. Infancy

      6. Intoxication

      7. Mistake

1. Introduction: The Theory of Defences and the Justification-Excuse Distinction

G. Williams, ‘The Theory of Excuses’ (1982) Crim LR 732 [law lib]

W Wilson, ‘The Structure of Criminal Defences’ [2005] Crim LR 108

2. Defences Denying Responsible Agency

[Insanity]

1. Two different claims

   1. D was insane at the time s/he committed the offence

   2. D was insane at the time of trial and so unable effectively to defend him/herself

2. Requirements

   1. Basic definition – (McNaghten)

      1. 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

   2. Disease of the mind

      1. 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 (Kemp)

            1. 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

            1. 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)

      2. 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

   3. Defect of reason

      1. 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

   4. D did not know quality or nature of his/her act

      1. 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 –

            1. 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’

            1. 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

   5. Not knowing the act is wrong

      1. ‘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

   1. Harper (1998) held that insanity was not a defence to a strict liability offence

      1. 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

   1. 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

   1. Key issue is whether D is able to understand the charge and the difference between guilty & not guilty pleas

   2. D’s mental capabilities must be sufficient for him/her to be able to conduct his/her defence adequately

      1. Includes – to challenge jurors, to instruct counsel, and understand the evidence (Robertson)

   3. 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

      1. 1991 Act includes disposals ranging from absolute discharge to admission to hospital with a restraining order

*Criminal Procedure (Insanity) Act 1964 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—

   1. a special verdict is returned that the accused is not guilty by reason of insanity; or

   2. 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—

   1. a hospital order (with or without a restriction order);

   2. a supervision order; or

   3. an order for his absolute discharge.

3. Where—

   1. the offence to which the special verdict or the findings relate is an offence the sentence for which is fixed by law, and

   2. 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).

The M’Naghten Rules (see M’Naghten’s Case [1843] 8 ER 718):

“to establish a defence on the ground of insanity, it must...

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