What the prosecution must prove, and the two defences

7.1Elements and proof

The prosecution bears the burden of proving both elements beyond reasonable doubt. Driving is rarely in issue; it is usually admitted at the roadside and recorded. Presence is proved by the certificate of analysis, which the Act renders admissible as evidence of the matters it states and, in the absence of evidence to the contrary, proof of them [review: the certificate provisions in Schedule 3 of the Act and the notice requirements for challenging a certificate]. The practical effect is a reversal of evidential burden on the presence element: the defence must point to evidence that the certificate is wrong, not merely put the prosecution to proof.

7.2The certificate: what can go wrong

The lines of challenge are procedural rather than scientific. Was the sample taken within the time permitted after driving? Was the confirmatory test conducted by an authorised officer using an approved device? Was the sample sealed, labelled and transmitted in accordance with the regulation? Does the certificate identify the drug by reference to the schedule? Did the defence receive the certificate within the time required, and did it serve the notice required to require the analyst's attendance? [review: the time limits for sampling after driving, understood to be two hours for oral fluid and four for blood] A practitioner reading a s 111 brief checks these mechanically, because a defect in any of them is the only realistic route to an acquittal.

7.3Honest and reasonable mistake

The defence under Proudman v Dayman was outlined in Lesson 1. Its operation for s 111 turns on whether the mistake is of fact and reasonable. The reported instances of success involve involuntary or unknowing ingestion; the reported instances of failure involve knowing consumption coupled with a belief about clearance time. The evidential burden is on the accused to raise the defence; once raised on the evidence, the prosecution must negative it beyond reasonable doubt. [review: identify NSW authority on the defence in the drug-driving context; the s 110 line of authority on "I did not know I was over the limit" is the usual analogy and it is uniformly against the accused]

7.4The consequence for advice

For most clients the honest advice is that the charge will be proved and the case is about sentence. That advice, given early, saves the client the cost of a defended hearing that fails and the loss of the plea discount. The two exceptions are real but rare, and the practitioner's job is to recognise them on the brief rather than to hope for them.