Self-defence is an available defence to protect individuals for charges that involve the use of threat or force but were founded on the belief that conduct was necessary under the circumstances. Successfully establishing self-defence can result in a finding of not-guilty for a charge. A person can only be found to be acting in self-defence if they believe the conduct was necessary to defend themselves or another person from the infliction of death or really serious injury.
Self-defence may apply as a defence where the person believes the conduct is necessary for self-defence and that the conduct is a reasonable response in the circumstances, as you perceive it. For example, if you assault someone when faced with a threat of serious injury, you can raise self-defence as a defence to your assault charge. In homicide cases, the defence can only be raised where the conduct is perceived to be necessary to defend yourself or someone else from ‘really serious injury’ (including sexual assault).
The law of self-defence is highly dependent on the specific circumstances of your case, especially what you perceived at the time of the alleged offence. Some issues that will be crucial to your case include:
- Your perception of the situation/threat;
- Your conduct/actions taken (especially whether it was proportional to the threat);
- The behaviour of anyone else in the situation.
Self-defence can be raised for some offences, including assault, manslaughter and murder. The defence may also be used where you acted with the intention to protect the property or to defend another person (in some circumstances). Common law self-defence has been replaced by statutory self-defence. However, common law self-defence may be available where:
- Your charge relates to an offence other than homicide; and
- The alleged offence was committed between 23 November 2005 and 1 November 2014.
Victoria abolished the defensive homicide offence in November 2014, an offence originally introduced for individuals who kill another, despite holding an unreasonable belief that they were acting in self-defence.  Defensive homicide no longer exists but may apply where the offence is alleged to have been committed on or after 23 November 2005 and before 1 November 2014.
Elements of Statutory Self-Defence
There are currently two elements for statutory self-defence:
- Necessity – You genuinely believed at the time that your acts were necessary under the circumstances (subjective element); and
- Reasonableness – The Prosecution is required to establish that your conduct is not a reasonable response under the circumstances, as you believed it to be (objective element).
Unlike Common law self-defence, statutory self-defence does not require a belief in necessity based upon reasonableness. The consideration for reasonableness is that you had a genuine belief at the time that your conduct was reasonable under the circumstances.
Onus of Proof
Similar to other offences such as Necessity or Duress, the Defence must provide evidence that signifies that self-defence possibly existed. However, if self-defence is raised, it is the responsibility of the Police (Prosecution) to prove that the elements of self- defence did not exist beyond all reasonable doubt. If either of the elements is not disproved by the Police, you may be entitled to an acquittal (a finding of not guilty).
 Crimes Act 1958 (Vic) 322K(3).
 Zecevic v DPP (Vic) (1987) 162 CLR 645.
 Crimes Act 1958 (Vic) s 322K(3).
 Crimes Act 1958 (Vic) s 322N.
 Crimes Act 1958 (Vic) s 9AD (now abolished)
 Crimes Act 1958 (Vic) s 322K (2)(a).
 Crimes Act 1958 (Vic) s 322K (2)(b).
 Crimes Act 1958 (Vic) s 322K
 R v Katarzynski  NSWSC 613.
 Crimes Act 1958 (Vic) s 322I.
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Views expressed in this article are not necessarily endorsed by Leanne Warren and Associates.