Self-Defence/Defence of Another/Prevention of Crime


  • Self-defence comes from common law
  • General defence - if successful -> complete acquittal
  • This defence allows a person to use reasonable force to
    • Defend himself from attack
    • Defend another from attack
      • E.g. R v Rose (1884) D shot father, who was attacking D's mother. D was acquitted on grounds of self-defence 
    • Defend his property
  • There is also Prevention of Crime - s3(1) Criminal Law Act 1967 - 'a person may use such force as is reasonable in the circumstances in the prevention of crime, or in ... assisting in the lawful arrest of offenders or suspected offenders ...'
  • Parlieament has partially consolidated self-defence + prevention of crime into s76 Criminal Justice and Immigration Act 2008
    • states: 'a person may use such force as is reasonable in the circumstances'
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Burden of Proof

  • Burden of proof on P to disprove D used self-defence
  • P must prove:
    • Use of any force = unnecessary, or if it was, then
    • The actual degree of force used was unreasonable
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The Necessity of Force

  • Was the force D used necessary? - for jury to decide
  • Crim Just Imm Act - a person is not under any obligation to retreat
    • But D not taking opportunity to retreat might be relevant in deciding if force = necessary

R v Bird (1985) (

  • D was hit by a man and D hit back in self-defence
  • Trial judge: self-defence only available if D had shown unwillingness to fight
  • Conviction quashed: an unwillingness to fight not necessary.
    • there are situations where D might reasonably react immediately w/out first retreating
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Pre-emptive Strike

  • D can use force to prevent an attack
    • D doesn't need to wait until he is being hit

Beckford v R (1988)

  • Lord Griffith: 'a man about to be attacked does not have to wait for his assailant to strike the first blow or fire the first shot; circumstances may justify a pre-emptive strike'

A-G Ref (no2 1983/84) (

  • D made petrol bombs during riots to protect his shop
  • Anticipated attack never happened + D did not use petrol bombs
  • Charged under Explosive Substances Act 1883
  • D successfully pleaded self-defence
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Attacker Retreats

  • If attacker = running away, highly unlikely that any force will be seen as necessary

Hussain and Another (2010) (

  • D was burgled
  • Burglars ran off but D and another fam member chased them
  • Caught one burglar + beat him up
  • Held: self-defence not available as danger from original attack had passed
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Mistaken Use of Force

  • Where D makes genuine mistake, jury will decide whether the force was necessary in the circumstances as D believed existed - Williams

Williams (1987)

  • D saw what looked like man assaulting youth
  • D asked man what he was doing + man said that he was PC arresting youth for assaulting old lady. D asked man to show police ID but man failed to do so
    • Struggle broke out between D and man
  • Trial judge: mistake would only be a defence if it was both honest and reasonable (objective)
  • CA: Conviction quashed: jury should have been directed to whether D's misktaken belief was genuine regardless of whether it was reasonable or not (subjective)

Crim Just + Imm Act 2008 s75(3)+(4)

  • 'The question of whether the degree of force used by D was reasonable in the circumstances is to be decided by reference to the circumstances as D believed them to be ... whether or not it was a mistaken belief ... or ... whether or not it was reasonable'
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Intoxicated Mistake (Voluntary intoxication)

A drunken mistake concerning the necessity for, or the amount of force required in self-defence is no defence - O'Grady, Hatton

O'Grady (1987) 

  • D killed V while drunk
  • D charged w/manslaughter 
  • Self-Defence failed
    • Since put into Statute - Crim Just + Imm Act 2008 - D cannot rely on a mistaken belief in relation to the necessity for, or amount of force used, if that mistake is due to D's involuntary intoxication

Hatton (2005) (

  • D killed V w/sledgehammer while drunk
  • D charged w/murder
  • Ruled that decision in O'Grady not limited to basic intent offences - drunken mistake regarding amount of force needed in self-defence -> not a defence
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Degree of Force

  • law allows reasonable force to be used in the circumstances
  • If the force used was disproportionate in the circumstances as D believed them to be, this is not reasonable
  • To decide whether force was reasonable the following will be taken into account
    • s76(7)(a) - ... a person ... may not be able to weight to a nicety the exact measure of any necessary action; and
    • s76(7)(b) - ... evidence of a person's having only done what they honestly and instinctively thought was necessary ... constitutes strong evidence that only reasonable action was taken ...'
      • summary: someone facing attack is likely to be under stress -> cannot be expected to weigh up accurately how much force to use in the situation. If he honestly and instinctively thought that the level of force used was necesary -> strong evidence that degree of force = reasonable in the circumstances
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Householder Cases

  • Crime and Courts Act 2013 ammended s76 Crim Just Imm Act 2008 to give wider defence to people when in their homes
    • Normally, degree of force not reasonable if force = disproportionate (in circumstances as D believed them to be)
    • w/householder cases, degree of force not reasonable if force = grossly disproportionate

To be a householder case

  • the force concerned is force used by D while in/partly in a building that is a dwelling
  • D cannot be a trespasser
  • D must have believed V to be a trespasser 

Note: also applies to residences that are also places of work (e.g. if D is a shopkeeper)

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If D has a Psychiatric Condition

  • If D's psychiatric condition makes him genuinely believe that force is necessary + courts accept this -> D should be able to use self-defence
  • But this is doubtful - Act did not make it clear whether a psychiatric condition would be taken into account or not
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