Defence of Honest and Reasonable Mistake

Whilst the adage of "Ignorance of the law' is no excuse holds true for many transgressions in this post we provide an overview on the defence of honest and reasonable mistake of fact.

Application and elements

The defence of honest and reasonable mistake of fact is a statutory defence under Commonwealth Criminal Code (see Part 9.2), and consequently may be relevant for commonwealth offences (excluding absolute liability offences).

In Victoria, the defence may be available under the common law principles.

There are 3 elements that must be established on evidence adduced by an accused (Proudman v. Dayman (1941) 67 CLR 536 and Jiminez v. the Queen (1992) 173 CLR 572; He Kaw Teh (1985) 15 A Crim R 204, 233):


- an honest and reasonable believed in a state of facts which if they existed, would make the defendant's act innocent.

- the belief was held on reasonable grounds

- the mistake belief must be as to a fact and not the law

An accused must adduce evidence to support the "existence of an actual or positive belief" (VonLieven v Stewart (1990) 21 NSWLR 52 at 66-67) or an “affirmative belief” (State Rail Authority v Hunter Water Board (1992) 65 A Crim R 101 at 104-105).


Consequently, mere inadvertence to the existence of certain facts is unlikely to be sufficient to raise the defence (VonLieven V Stewart (1990) 21 NSWLR)


A defence of honest and reasonable mistake of fact not available for all offences

Unless a criminal offence is one of absolute liability or strict liability, the prosecution must prove an accused committed an offence with the requisite intent or responsibility.


Absolute liability offences describe a category of offences whereby the prosecution does not have to prove a guilty mind or intention on the part of an accused person. Drink driving is an example of an offence whereby the intention of the driver will be irrelevant.


Drive unregistered motor vehicle is another example of an absolute liability offence. In some cases, the statutory instrument that contains the offence will also prescribe whether the offence is one of absolute or strict liability.


Strict liability offences do not require the prosecution to prove the intention or guilty mind of an accused but may still permit a defence of honest and reasonable mistake of fact.


Always get legal advice as to the availability of the defence

The foregoing discussion was general in nature, it is always important to consult a criminal defence lawyer about defending a criminal allegation. An experienced criminal lawyer will provide advice about the availability of any defences upon careful consideration of the prosecution brief of evidence.


If you are facing a criminal charge, call our office on 03 9668 7600 for a no fee case assessment.


Other useful links:


Judicial College of Victoria. Refer to Criminal Charge Book.







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