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Defence of Honest and Reasonable Mistake of Belief

The defence of honest and reasonable mistake of belief may apply where a person conducts themselves in a certain way, and does so in an honest belief that they are entitled to do so. In these circumstances, that person is entitled to raise the defence of honest and reasonable mistake. The act would not have been committed with a guilty mind. The defence of honest and reasonable mistake of belief can only be raised in cases of strict liability. In these types of cases, there is no requirement for the prosecution to prove that an accused intended the result to occur.

In Victoria, there is a defence of honest and reasonable mistake that arises from case law and from Commonwealth legislation. The law with respect to Commonwealth offences can be found in sections 9.1 to 9.4 of the Criminal Code Act 1995. These sections state that a person is not criminally responsible for an offence if at the time of committing the act, the person is under a mistaken belief about, or is ignorant of, facts and the existence of that mistaken belief or ignorance negates the fault element, or was reasonably held.

In cases of strict liability, a person is not criminally responsible for an offence if at the time the offence was committed, the person considered whether or not facts existed and was under a mistaken, but reasonable belief about those facts; and had those facts existed, the conduct would not have constituted an offence.

Who Has to Prove What?
An accused that raises the defence of honest and reasonable mistake of belief carries the evidentiary burden to prove it. This means that the accused needs to produce evidence to support the basis for the defence. The evidence must show that the accused’s actions were both honest and reasonable. The prosecution are then required to prove that no such belief was held and/or that it was held unreasonably.