This week the Queensland opposition launched a robust attack on a centuries-old criminal law defence.

The ‘mistake of fact’ defence was encoded into Queensland law in 1899 when our Criminal Code was first enacted, adopting a common-law notion dating back at least as far as pre-Norman England, that criminal liability requires some sort of actual subjective culpability, whether based on moral guilt or negligence. Section 24 of our Code provides that a person who does something under an honest and reasonable, but mistaken, belief as to a particular fact, they are not criminally responsible to any greater extent than if that belief was correct.

So if, for example, someone walks into your house in the middle of the night brandishing a knife, and as a result you honestly believe you are under physical attack, so you strike out at them to defend yourself, you can rely on a defence of self-defence, even if the intruder swears they had no intention of hurting you. It doesn’t matter what was actually in their mind, provided you honestly, albeit perhaps mistakenly, believed they were attacking you, and the jury accepts that it was reasonable for you to have that belief in all the circumstances.

But this week the LNP vowed to overhaul the “archaic legal loophole,” arguing it allows rapists to walk free by claiming they were so drunk they thought their victim was consenting, after the Courier Mail newspaper reported that a rape survivor was told by police officers that mistake of fact would be used to discredit her complaint. Leader Deb Frecklington has promised a review of Queensland’s mistake of fact defence in rape and sexual assault cases, and has urged Attorney General Yvette D’Ath to refer the matter to the Queensland Law Reform Commission (Q LRC) for immediate review. Meanwhile, LNP Shadow Attorney-General David Janetzki has said the mistake of fact defence was setting “an alarming precedent denying victims justice.”

Is it? The state’s peak law bodies certainly don’t think so. The Queensland Law Society has blamed the controversy on “confusion and even misinformation” about how the defence works, and the Queensland Bar Association president Rebecca Treston QC says no change is needed, adding that it is “not the case that defendants can simply claim that they thought the complainant was consenting because they were intoxicated, and expect to be acquitted on that basis.”

So what’s the truth? Can rapists rely on a ‘mistake of fact’ defence on the basis they drunkenly believed their victim was consenting? No, they can’t.

The ‘mistake of fact’ defence does not apply just because someone “claims they were so drunk they thought their victim was consenting.” The mistaken belief has to be shown to be both honestly held and, importantly, demonstrably reasonable in all the circumstances. In other words, a jury hears all of the relevant detail of what happened and then determines whether, given those facts, it was reasonable for the accused to form that belief. If it wasn’t, the defence simply does not apply.

Properly understood, the ‘mistake of fact’ defence is certainly not some sort of archaic, technical “legal loophole” aimed at protecting the guilty. On the contrary, the defence is designed to exonerate the innocent. When its application is properly and sensibly considered, it is easy to understand why the defence has endured for many centuries, because it is absolutely and essentially in line with ordinary, common sense concepts of what is fair and right and reasonable in everyday human interaction. It is exactly the standard every one of us would hope and expect to be applied if we or any of our loved ones were accused of criminal behavior.

Is it true, as reported, that police tried to dissuade a rape survivor by telling her mistake of fact would be used to discredit her complaint? Who knows? If they did, they shouldn’t have, because that’s simply not a call for the police to make; it’s for a jury to decide. If the complaint was made, the charge should be laid and duly prosecuted. If and when it came before a jury, a mistake of fact defence would only arise if, after listening to what all the witnesses had to say, twelve ordinary jurors accepted firstly that the accused truthfully and honestly held a mistaken belief and secondly, in all the circumstances of everything that happened, it was reasonable for him to hold that belief.

Could ‘mistake of fact’ be better defined or refined in the context of sexual offences? Perhaps. Is it worth seeking the advice of someone like the Queensland Law Reform Commission to see if we can do things better? Of course.

But rushing with an obscene haste, dictated by a pre-determined view that mistake of fact should be abolished, or even qualified, in any circumstance, is entirely ill-advised. This law has been around, in one shape or another, for centuries. But that doesn’t make it archaic per se. Anyone who truly understands it will conclude it is based on nothing more than everyday common sense.

Chris Nyst, Lawyer, Novelist and Film Maker

Chris Nyst - Criminal Lawyer