A review of general defences: Necessity
Usually acquits a defendant of a crime, unless insanity is proved
By this, they are ‘not guilty by reason of insanity’
Capacity defences: Insanity, Automatism, Intoxication
Necessity Defences: Duress, Self-defence
Self-defence/ prevention of crime
1. Public defence: In the interests of the public and defined under S3 of the Criminal
Law Act 1967. “A person who may use such force as is reasonable in the
circumstances in the prevention of a crime”
2. Private defence: In the interests of oneself, others and property
This defence can be relied on if their action was necessary due to:
a threat of unjustified harm to themselves
a threat of unjustified harm to someone else or to property
a need to prevent a crime
Was the force necessary?
1. Whether the person could have retreated from the situation (Bird – ex appeared at
birthday broke into a fight after he slapped her)
2. Whether the threat was imminent (Malnik v DPP 1989)
3. Whether the defendant made some mistake which caused them to think the action was
justified (Gladstone Williams 1971 – attacked a person who was actually tackling
someone who had just mugged another person)
What is reasonable force?
• Was the force used proportionate to what was done to D? (Clegg)
• Was the force considered excessive in the circumstances? (Martin)
Mistake and self-defence
If there was a genuine mistake on facts, then mistake can be used with self-defence
(Williams 1987) but a drunken mistake will not be self-defence
Duress
Defined as: Where a person commits a crime because they were acting under threat of death
or serious personal injury to themselves or another. This could also fall within self-defence.
R v Symonds (1998) - Self-defence should be the preferred defence for offences against the
person and duress for other offences such as theft or robbery.
There are two types of duress: duress by threats and duress by circumstances
Usually acquits a defendant of a crime, unless insanity is proved
By this, they are ‘not guilty by reason of insanity’
Capacity defences: Insanity, Automatism, Intoxication
Necessity Defences: Duress, Self-defence
Self-defence/ prevention of crime
1. Public defence: In the interests of the public and defined under S3 of the Criminal
Law Act 1967. “A person who may use such force as is reasonable in the
circumstances in the prevention of a crime”
2. Private defence: In the interests of oneself, others and property
This defence can be relied on if their action was necessary due to:
a threat of unjustified harm to themselves
a threat of unjustified harm to someone else or to property
a need to prevent a crime
Was the force necessary?
1. Whether the person could have retreated from the situation (Bird – ex appeared at
birthday broke into a fight after he slapped her)
2. Whether the threat was imminent (Malnik v DPP 1989)
3. Whether the defendant made some mistake which caused them to think the action was
justified (Gladstone Williams 1971 – attacked a person who was actually tackling
someone who had just mugged another person)
What is reasonable force?
• Was the force used proportionate to what was done to D? (Clegg)
• Was the force considered excessive in the circumstances? (Martin)
Mistake and self-defence
If there was a genuine mistake on facts, then mistake can be used with self-defence
(Williams 1987) but a drunken mistake will not be self-defence
Duress
Defined as: Where a person commits a crime because they were acting under threat of death
or serious personal injury to themselves or another. This could also fall within self-defence.
R v Symonds (1998) - Self-defence should be the preferred defence for offences against the
person and duress for other offences such as theft or robbery.
There are two types of duress: duress by threats and duress by circumstances
