- The rules of the defence were developed under the case of M'Naughten (1843): "At the time, the defendant was labouring under such a defect of reason and disease of the mind as not to know the nature and quality of the act or that the act was wrong"
- Defect of reason = this means an inability to use powers of reason, not just a failure to do so as seen in Clarke
- Disease of the mind = this relies heavily upon a legal definition as opposed to a medical one
- Kemp = Brain was not 'diseased', his condition was a temporary one but it counted
- Bratty = if it is likely to reoccur, then it counts
- Burgess = sleepwalking counts because of internal factor thus making it 'insanity'
- Diabetes = for insanity, if the offence was caused by a hyperglycaemic state (too high bloodsugar levels meaning the defendant likely ate but did not take insulin) then it is insanity as it was caused by an internal issue (bloodsugar levels) - Henessey
- Defendant does not know that the act was wrong = this refers to it being legally wrong
- Windle = "I suppose I'll hang for this" shows defendant understood it to be legally wrong
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- The law cannot hold someone responsible if they could not have helped it due to a completely involuntary action as a result of an external factor that was not self-induced
- Completely involuntary action:
- "An act which is done by the muscles but without any control by the mind" (Bratty)
- A.G.'s ref no 2 1992: must be total loss of voluntary control
- External factor = cannot result from defendant's actions or failure to act
- Hill v Baxter: developed the swarm of bees principle (protecting yourself against a swarm would equal total loss of voluntary control as opposed to just one bee)
- Whooley: Sneezing fit is external factor
- Diabetes = unlike insanity, must be caused by a hypoglycaemic state (insulin too high, bloodsugar levels too low - have taken insulin but not eaten) as this is an external factor (Quick)
- Not self-induced:
- If defendant knowingly puts himself in automaton position, cannot be used (Bailey)
- If defendant does not know that the act will lead to a state of automatism, then the defence can be used (similar to the principle developed by Hardie for Intoxication)
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This defence includes drink, legal drugs, illegal drugs and solvent abuse
1) Were the defendant's action a result of being intoxicated?
- Yes = defence can be used (Sheehan and Moore 1975)
- No = no defence - if mens rea formed prior to intoxication, then defence is not available (Kingston; AG for NI v Gallagher ~ dutch courage)
2) Was the crime basic or specific intent?
- Specific = can be used as inability to form necessary mens rea of intent
- Basic = cannot be used as Majewski says that to get intoxciated is reckless so fulfills basic intent mens rea requirements. HOWEVER, if the defendant was involuntarily intoxicated (i.e. had drink spiked) then defence can be used for basic intent crimes
3) Was the intoxication voluntary or involuntary?
- Voluntary = no defence (unless specific intent crime, see question 2) as reckless to get intoxicated. (Allen)
- Involuntary = always a defence for both basic and specific intent (Hardie)
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- Was the consent genuine?
- Consent obtained by fraud = not accepted (Tabassum)
- Looks at whether the victim had sufficient understanding and intelligence to give consent (Burrell v Harmer)
- Can person consent to the act?
- Cannot consent to death (Dianne Pretty, Tony Nicklinson)
- Brown says that you cannot consent to more than a battery unless it falls under one of the recognised exceptions:
- Properly conducted games and sports = excessive force can be used in the heat of the moment (Barnes, Michael Watson)
- Normal social intercourse = everyone gives implied consent to everyday touching (Pringle, Collins v Willcock)
- Medical Procedures, Tattoos and Piercings
- Horseplay = no offence if defendant did not intend harm and believed the victim to be consenting to the horseplay (Jones)
- Sexual Acitivites = law does not concern itself with these unless it strays onto an issue of morality (Brown, Dica)
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Self-Defence/Prevention of Crime
- It is a total defence which would lead to acquittal in order to help vitcims of crime who were simply trying to protect themselves
- Was the force necesary?
- Necessary in the circumstances as D believed them to be - subjective (Gladstone Williams)
- If the mistake arises out of intoxication or medical condition, you cannot use the defence
- Can be a pre-emptive strike if you genuinely believe you are going to be attacked (A.G.'s ref no 2 1983)
- There is no duty to retreat (Bird)
- Cannot use the defence if you incite the violence (Keane 2010)
- Was the force proportionate?
- Palmer: The jury will decide if so depending on each different case (Objective)
- Situations where defence is not allowed:
- Attack is over an no peril remains (Munir Hussain, Tony Martin, Clegg)
- Retaliation is out of proportion to the necessities of the situation
- The defendant does not need to make an entirely correct decision in the heat of the moment
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