General Defences

• What are the general defences?

  • Mistake
  • Self-defence
  • Intoxication
  • Automatism
  • Insanity
• Mistake 


  • A general and complete defence
  • Mistake of law is not a defence
  • A mistake of fact or some circumstances or misunderstanding the situation
  • Doesn't need to be reasonable as long as it is genuine
• What were the facts of Morgan (1975)


  • 2 men were invited by a man to have sex with him and his wife
  • The man wasn't her husband and she resisted and was raped and sustained physical injuries
  • All 3 were convicted of rape
  • The first two appealed as they thought she was consenting due to the information given
  • The court said it wasn't a reasonable mistake
• Sexual offences and the defence of mistake

  Mistake in relation to the victim's consent must have been honest and reasonable
• Murder and the defence of mistake


  Mistake in the victim's identity isn't sufficient
• Strict liability offences and the defence of mistake 


  Not applicable
• To raise the defence of mistake, the defendant must provide evidence of the mistake
• Self-Defence


  • Definition: When the defendant uses force to defend themselves, their property, or another person
  • A complete and justificatory defence
  • Includes self defence, defence of property, prevention of crime and effecting lawful arrest
• What elements are needed to identify self defence

  • A trigger and a response are needed as defined in Palmer (1971)
  • Trigger - The defendant believed use of force to be necessary
  • Response - Type and degree of force used by the defendant was reasonable
• Self defence - trigger


  • A mistaken belief is acceptable - Williams (Gladstone) (1984): Mr Williams saw a man being attacked and punched the attacker who was actually the victim
  • Pre-emptive strikes are acceptable - Beckford (1987) - She hit her boyfriend in the head with a glass causing him to lose an eye, he was holding her up against a wall and was going to hurt her
• Self-defence - response


  • A subjective and objective test
  • Was the defendant's response to the threat proportionate to the circumstances?
  • Was the type and amount of force reasonable based on the fact of how they saw it to be?
  • Martin (Anthony) (2003) - Had a gun to protect his house and was burgled and shot the robbers in the back, found to be disproportionate
• Intoxication


  • Only available when the defendant acted under extreme intoxication - the defendant couldn't form the mens rea
  • Reduced inhibition doesn't apply and intent cannot be formed before intoxication
  • Burden of proof lies with the prosecution to disprove defence
• Voluntary intoxication and specific intent offences

  • The mens rea is satisfied only by intention - murder, inflicting GBH with intent, burglary
  • Voluntary intoxication may be a complete defence if no mens rea was formd
  • Defendant would be charged with recklessness-based counterpart of the offence
• Voluntary intoxication and basic-intent offences


  • The mens rea is satisfied by intention or recklessness - common assault, rape, ss.47/20 OAPA
  • Voluntary intoxication is a proof of mens rea
• Involuntary intoxication


  • Unexpected effects of non-dangerous drugs or prescribed medication
  • E.g., a spiked drink
  • A general and complete defence
  • Only available if the defendant couldn’t form mens rea
  • Available if the defendant was unaware of the effects of a non-dangerous drug
  • Not available if the drug is known to be dangerous
• Automatism

  • An external factor causes the defendant to have uncontrolled bodily actions
  • General and complete defence
  • No actus reus
  • Requires a total loss of control over bodily acts caused by an external factor
• Automatism - Total loss of control

  • Partial or reduced bodily control is insufficient
  • AG's Ref No.2 of 1992 (1994) - Drove all night but wasn't fully aware due to long hours and crashed the lorry into a car
  • Raised the defence of automatism but it was unsupported as he had partial loss of control
• Automatism - caused by an external factor

  • Tensions of everyday life aren't sufficient as an external factor
  • Self-induced automatism normally isn't acceptable
  • Lipman [1970] - The defendant took a large amount of LSD and hallucinated that he was being attacked by snakes while being swallowed by the earth, he fought back the snakes who were his friend and died
• What is the procedure for raising automatism

  • The defendant must present evidence to prove it (includes medical evidence)
  • The burden of proof lies with the prosecution to prove they had actus reus
• Insanity


  • A legal construct but a general defence that negates liability
  • The defendant could be sent to a mental facility for life if successful
• What is the definition and elements of insanity

  • “At the time of committing the act, the defendant was labouring under such a defect of reason, from a 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 what he was doing was wrong.” - M'Naghten [1843]
  • Relies on a disease of the mind which caused the defendant a defect of reason and the defendant didn't know the nature and quality of their act or didn't know what they were doing was wrong
• What is a disease of mind?

  • Any disease which affects the functioning of the mind
  • Isn't limited to psychotic illnesses but covers epilepsy, diabetes and sleepwalking
  • Has to have existed at the time of the act
• What is the procedure for raising insanity?

  • The burden of proof lies with the defendant on the balance of probabilities
  • The defendant should provide medical evidence