Drug Driving and the Defence of "Honest and Reasonable Mistake of Fact": Case Law Update

19 SEP 2023


In criminal law, an individual may find themselves caught in a confusing situation where they acted under a genuine and reasonable misconception of certain facts. In such instances, the defence of an "honest and reasonable mistake of fact" comes into play.


Understanding the "Honest and Reasonable Mistake of Fact" Defence

Simply put, this defence is based on the belief that an individual made an honest error about certain facts, and anyone in the same situation might have made a similar mistake.

Let’s illustrate this with a practical example: Imagine a person unknowingly drank some water from a bottle that was in the car, and the bottle contained illicit drugs. They later drove the vehicle not knowing they were under the influence. This defence would argue that, given their genuine belief, they didn't intentionally drive the vehicle while under the influence. This is what took place in Narouz v R, and below we outline what it means for you.


Chandiran v R [2022] NSWDC 576

In the 2022 case of Chandiran v R, the Court found themselves navigating the complexity of this defence in the context of drug-driving laws. The defendant was prosecuted under section 111(1) of the Road Transport Act, which is concerned with the presence of illicit drugs in a person's oral fluid, blood, or urine while driving.

During the proceedings, there was significant emphasis on whether the defendant had the opportunity to raise an "honest and reasonable mistake of fact" as a defence to the charge. His Honour Scotting DCJ found, that this defence could indeed be raised. According to Scotting DCJ, this belief was based on the notion that it might be challenging for a person to evade liability if they are unaware of how they were exposed to the illicit substance and its presence in their system.

However, the opposing viewpoint argued that this defence could not overcome the explicit wording of the provision.


Narouz v R [2023] NSWDC 293

This case considers that the provision of section 111(1) of the Road Transport Act, clearly states that to establish someone's guilt, the prosecution only needs to prove the presence of an illicit drug in the person's oral fluid, blood, or urine, irrespective of their awareness or the circumstances leading to the drug consumption.

This view essentially suggests that "honest and reasonable mistake" doesn't find solid ground within the wording of the legislation, focussing more on the proof of the drug's presence rather than the defendant's perception or understanding of their actions.

In this case the defendant was consistent in denying usage of cocaine and proposed potential explanations for its presence in his system, including drinking from a bottle found in a friend’s car. The Court dismissed the appeal against the conviction, emphasizing that the presence of the illicit drug in his oral fluid was sufficient to uphold the charge.

The Chandiran v R case opened up a world of discussion on applying the "honest and reasonable mistake of fact" defence. However, as seen in Narouz v R, there is a clear divide on its application, especially concerning drug driving laws.

This case serves as an important reminder for individuals to be well advised on the evolving landscape of criminal law. If you ever find yourself navigating similar uncertain times, seeking expert legal advice is crucial.


The contents of this publication are for reference purposes only. This publication does not constitute legal advice and should not be relied upon as legal advice. Specific legal advice should always be sought separately before taking any action based on this publication.


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POSTED: 20 Nov 2023
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