Self-defence is a commonly relied-upon defence in response to assault charges and other offences involving the unlawful use of force.  A person is not guilty of an offence if they were acting in defence of themselves or of another person.  This article outlines self defence law in NSW.

In New South Wales, provisions relating to self-defence are contained in Part 11, Division 3 of the Crimes Act 1900 (the Act).

Most relevantly, section 418 of the Crimes Act, 1900 (NSW) provides that:

• A person is not criminally responsible for an offence if the person carries out the conduct constituting the offence in self-defence.
• A person carries out conduct in self-defence if and only if the person believes the conduct is necessary—
  to defend himself or herself or another person, or
  to prevent or terminate the unlawful deprivation of his or her liberty or the liberty of another person, or to protect property from unlawful taking, destruction, damage or interference, or
  to prevent criminal trespass to any land or premises or to remove a person committing any such criminal trespass,
  and the conduct is a reasonable response in the circumstances as he or she perceives them.

In R v Katarzynski [2002] NSWSC 613 (which has been frequently applied and approved) the Supreme Court of NSW established that when self-defence is raised, a jury is to consider the following questions:

• Is there a reasonable possibility that the accused believed that his or her conduct was necessary in order to defend themselves?; and
• If there was such a reasonable possibility, is there also a reasonable possibility that what the accused did was a reasonable response to the circumstances as they perceived them?

The first question is determined from a completely subjective point of view, considering all the personal characteristics of the accused at the time he or she carried out the conduct. The second question is an objective assessment of the proportionality of the accused’s response to the situation the accused subjectively believed he or she faced.

In other words, whether something qualifies as ‘self defence’ under Section 418 of the Act depends greatly on the circumstances of the case and depends significantly (but not wholly) on the subjective point of view at the time the alleged ‘self defence’ occurred – but how proportional and reasonable the action they took was is an objective test, independent of any belief of the person.

The Crown (i.e. the prosecution) can negative self-defence if it proves – beyond a reasonable doubt, either:

• That the accused did not genuinely believe that it was necessary to act as they did in their own defence; or
• That what the accused did was not a reasonable response to the danger, as he or she perceived it to be.

Section 419 of the Act provides that the Crown (i.e. the prosecution) has the onus of proving, beyond reasonable doubt, that a person did not carry out conduct in self-defence.
Note that Section 420 of the Act provides that self defence is not available as a defence where a person uses force and either intentionally or recklessly inflicts death only:

• To protect property; or
• To prevent criminal trespass, or remove a person committing criminal trespass.

In other words, it cannot be ‘self-defence’ to kill another, or be so reckless in the use of force as to cause their death, if you do so to merely protect property or stop a trespass (for example, a thief in a store).

Section 421 provides that if a person uses force that involves the infliction of death, and the conduct is not a reasonable response in the circumstances as he or she perceives them, but the person believes that conduct is necessary:

• To defend himself or herself or another person; or
• To prevent or stop the unlawful deprivation of his or her liberty or the liberty of another person,

Then that person is not criminally responsible for murder, but – on a trial for murder – that person is to be found guilty of manslaughter.

Dorian Kratsas BA, LLB, LLM, GradCertLegP
Solicitor of the High Court of Australia & the Supreme Court of New South Wales
under the Legal Profession Uniform Law
Law Society No. 46208