You are not criminally responsible for an offence in New South Wales if you acted out of necessity, which is where:
1. You honestly believed on reasonable grounds you or a person you were bound to protect were placed in a situation of imminent peril,
2. Your conduct was intended to avoid that peril, and
3. Your conduct was proportionate to the avoidance of that consequence.
If you are able to raise evidence of necessity, the onus then shifts to the prosecution to prove beyond a reasonable doubt that the defence does not apply in the circumstances.
You are entitled to an acquittal if the prosecution is unable to do this.