What is the Legal Defence of Honest and Reasonable Mistake?
When a person inadvertently commits an offence because they hold a mistaken belief that they are entitled to do what they did, this may amount to a defence of an honest and reasonable mistake of fact. An honest and reasonable mistake negates as a defence in criminal law ‘mens rea’. That is, the accused lacks a guilty mind when committing the offence.
The defence of honest and reasonable mistake can be raised in response to strict liability offences. A strict liability offence is one in which the prosecution does not need to prove that the accused intended to commit the offence. There are many examples of strict liability offences under the Crimes Act 1958 (Vic), but the honest and reasonable mistake defence is often used in relation to charges such as:
Honest and Reasonable Mistake as a Defence in Victorian Criminal Law
In Victoria, the defence of honest and reasonable mistake traditionally arises out of common law. A key case in relation to the defence is Proudman v Dayman .
The defence of honest and reasonable mistake of fact also applies to Commonwealth offences. Division 9 of the Criminal Code Act 1995 (Cth) deals with offences involving mistakes. The legislation provides that a person is not criminally responsible for an offence if:
- At or before the time of the offence, the person considered whether or not facts existed;
- At the time of committing the act, the person was under a mistaken but reasonable belief about those facts; and
- Had those facts existed, the conduct would not have constituted an offence.
Proving an Honest and Reasonable Mistake defence in Court
Three elements are required to prove the defence of honest and reasonable mistake of fact:
- The mistaken belief must be honest (a subjective test);
- The mistaken belief must be reasonable (an objective test); and
- The mistake must be as to fact and not law.
In Victoria, the accused has the evidential burden of raising the honest and reasonable mistake defence. That is, the accused must present or point to evidence that they were under a reasonable but mistaken belief of facts at the time of committing the offence. Once the defence is raised, the prosecution must prove beyond a reasonable doubt that the mistaken belief was not honestly held or reasonable, or was not a mistake of fact.
To decide whether the mistaken belief was both ‘honest’ and ‘reasonable’, the Victorian courts rely on case law.
A mistaken belief is considered ‘honest’ if the accused forms their own positive belief. Merely being ignorant to a fact does not constitute an ‘honest’ belief (Proudman v Dayman ). Further, if evidence provides an inference or hypothesis that is consistent with innocence, the trier of facts must give the accused the benefit of the doubt in relation to that inference (Knight v R (1992)). This applies when considering what might be the honest belief of the accused. That is, if the evidence infers that the accused held an honest belief, the court must give the accused the benefit of the doubt.
A mistaken belief is considered ‘reasonable’ if at (or before) the time of the offence, the accused expressly considered whether or not a particular fact existed. If the accused does not consider the fact at all (i.e. is negligent or ignorant), the mistake cannot be considered ‘reasonable’ (He Kaw Teh v The Queen ). Further, the case of Mei Ying Su and Others v Australian Fisheries Management Authority and Another (no2) (2008) states that a mistaken belief is reasonable if:
- The belief is held by the accused;
- The belief is objectively reasonable (being rational, based on reason or capable of sustaining belief); and
- The belief is considered objectively reasonable when assessed by reference to the subjective circumstances in which the accused was placed (including the accused’s personal attributes and the information available to them at the time).
If the prosecution fails to disprove the defence of honest and mistaken belief, the accused will be acquitted.
Obtaining Legal Advice
Often, defendants can prove that their mistaken belief was ‘honest’ but fail to prove that it was ‘reasonable’. If you have been charged or are under investigation for allegedly committing a criminal offence, please contact our team at Sher Criminal Lawyers. We will help you achieve the best possible outcome by applying our extensive legal experience and expertise. One of our criminal law specialists will assess whether honest and reasonable mistake or any other defence is relevant to your case before planning a unique and calculated legal strategy. We are available 24/7 and offer free consultations by way of Zoom, Facetime or in person at our Melbourne and Moorabbin offices.