1. DEFENCES TO CRIMINAL
CHARGES

2. What is the point of a legal defence?
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Legal defences allow the accused to argue that they
had reduced liability (i.e. they were not responsible
for their actions).
Most legal defences argue that the accused did not
have the necessary mens rea to be found guilty of
the crime.
Legal defences help to achieve justice for the
accused; they allow the judge or jury to be lenient
in certain circumstances.

3. Complete Defences

Will result in the
accused being
acquitted of all
charges
Partial Defences

May result in the
charge or sentence
being reduced

4. Complete Defences
Mental illness or
insanity
• Difficult to prove
• Means the accused was unable to form the mens rea at the
time of the offence due to mental incapacitation
Involuntary behaviour
(automatism)
• Means that the accused could not control his behaviour at
the time of the crime
Mistake
• Not usually an appropriate defence
• Means that the accused made a genuine and reasonable
mistake in committing the crime
Self-defence
(necessity)
• Means that the accused carried out the crime to protect
themselves, another or property, to prevent a crime
• Force used must be “reasonable”
Duress
• Means that the accused committed the crime against their
free will, because their life was under threat
• Not acceptable for murder
Consent
• Generally used in sexual assault cases
• Means the “victim” gave permission for the act
• Not acceptable for murder

5. Partial Defences
Provocation
• The accused claims that their actions were a direct result of
the other person’s actions – i.e. the victim is partially
responsible because they caused the accused’s behaviour
• No longer a defence in Vic, WA or Tas. In NSW, can only be
used to reduce a murder charge to manslaughter.
Diminished
responsibility
• AKA “substantial impairment of responsibility”
• The accused claims that they suffer from a mental impairment
or abnormality that caused them to act a certain way and
commit the crime

6. Relevant Cases
Research
these cases.
Explain the
defence used
in each of
them.
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M’Naghten Test
R v Zecevic (1987)
R v Williamson (1972)
DPP v Morgan and others (1976)
R v Camplin (1978)
Osland v R (1998)