Mistake of Fact
Mistake of fact is a defence to a criminal charge where the accused honestly held a mistaken belief about a factual matter that, if true, would mean they did not commit the offence. The defence operates by negating the mens rea — the mental element — required for conviction. Where the Crown cannot prove that the accused knew (or was reckless or wilfully blind about) the prohibited facts, the accused must be acquitted.
Mass Tsang's criminal lawyers raise mistake of fact wherever the facts support it. For more, see our blog post on mistake of fact and mistake of law.
The core principle
The Supreme Court's leading authority is R v Beaver, 1957 (still cited today). An accused cannot be convicted of an offence requiring subjective mens rea where they honestly believed in a state of facts that would have made their conduct innocent. The mistake must be honest — not necessarily reasonable, in most contexts — but it must be genuine. Recklessness or wilful blindness about the underlying facts defeats the defence.
Common applications
Mistake of fact arises across the Criminal Code. Common examples include: in theft and fraud, a colour of right based on a mistaken belief in entitlement; in possession of stolen property, an honest belief the goods were obtained legitimately; in drug possession, an honest belief that a substance was not a controlled drug; in assault, an honest but mistaken belief that the complainant consented to the contact (subject to special rules in sexual assault); and in possession of child pornography, an honest belief that the depicted person was an adult.
Sexual assault — the special rules
In sexual assault, the mistake-of-consent defence is sharply limited by section 273.2. The defence is unavailable where: the accused's belief arose from self-induced intoxication, recklessness, or wilful blindness; the accused did not take reasonable steps to ascertain that the complainant was consenting; or the complainant was incapable of consenting or expressed a lack of consent. The reasonable-steps requirement is the most important limit.
Air of reality threshold
Before mistake of fact is left to the trier of fact, the trial judge must determine whether there is an "air of reality" to the defence — whether a properly instructed jury could reasonably acquit on the basis of the defence. The threshold is low but not nil. Pure speculation without evidentiary foundation does not raise an air of reality.
Mistake of fact vs. mistake of law
Mistake of fact is a defence; mistake of law is generally not. The maxim ignorantia juris non excusat (ignorance of the law is no excuse) is codified at section 19 of the Criminal Code. The line between the two can be subtle — for example, a belief about the legality of an act is mistake of law, but a belief about the facts that determine legality (the value of property, the age of a complainant) is mistake of fact.
Related glossary terms
