Week 19 Criminal: Public and Private Defence (self-defence)

what are the main types of public and private defences in criminal law?

• self-defence

• defence of another

• defence of property

• prevention of crime

• lawful arrest/apprehension

what laws codify public and private defences?

• s.76 CJIA 2008 - restates common law self-defence, also covers defence of others and property

• s.3 Criminal law Act 1967 - prevention of crime/arrest

• s.5 Criminal Damage Act 1971 - defence of property (if criminal damage involved)

what are the two general issues in a self-defence claim?

1. did V pose an unjustified, immediate threat?

2. was D’s response necessary and proportionate?

when is a threat considered ‘unjustified’?

• if D did not provoke violence - threat is unjustified by default

• if D did provoke, check Keane: defence may still apply unless D manipulated V into attacking

what if D makes a mistake about the threat?

• if honest belief (even if unreasonable), defence applies - see Gladstone Williams [1984] and s. 76 (4) (b) CJIA

• if mistake is due to voluntary intoxiaction - defence fails (R v Hatton [2005] s. 76(5) CJIA)

Does the threat have to be immediate?

Yes - force is only justified against an imminent threat

pre-emptive strikes are allowed if attack is honestly believed to be imminent (Devlin v Armstrong [1971], Beckford v R [1988])

what must D be trying to do in response to the threat?

Defend self, another, property, or prevent a crime

how is the necessity and reasonabless of the force assessed?

• subjectively - force must be based on what D honestly believed necessary

• objectively - degree of force must not be disproportionate (s. 76 (6) CJIA)

what if D used too much force?

• if disproportionate, defence fails

• s. 76(7) : courts consider human stress - not expected to “weight to a nicety”

• if force was honestly and instictively believed necessary, this is strong evidence of reasonableness

how is force assessed differently in householder cases?

• force must be grossly disproportionate (s.76(5A) CJIA)

• jury can still find disproportionate force reasonable (as in Collins [2016]) unless it is grossly disproportionate

is D required to retreat before using force?

• no duty to retreat - s.76(6A) CJIA

• but willingness to retreat may support necessity of later force (Bird [1985])

can D rely on a mistaken belief caused by mental illness?

• no - evidence of psychiatric disorders that affect danger perception is inadmissable in self-defence (R v Martin [2001])

• such cases may instead fall under diminished responsibility

what is the Dadson principle in self-defence?

D cant rely on self-defence if they didnt know they were acting defensively, even if the threat actually existed

what is the role of necessity in criminal law?

• used as a safety net defence - vague by design

• only applies in exceptional circumstances (e.g. medical cases)

when has necessity been accepted in medical cases?

• Gillick [1985] - prescribing contraception to underage girl

• F v West Berkshire [1989] - sterilisation of psychiatric patient without consent

can necessity justify murder?

• generally, no - as in Dudley & Stephens [1884]

• Exceptionally: Re A (Children) [2000] allowed separation of conjoined twins (one would die) based on necessity

what has the Law Commission said about necessity?

1977: recommended abolishing necessity defence

1993: recommended it stay uncodified to function as a safety net