Kingston (a pseudonym) v The Queen; Maxwell (a pseudonym) v The Queen

In *Kingston v The Queen* and *Maxwell v The Queen*, the applicants appealed their convictions for trafficking a large commercial quantity of butanediol in South Australia. The central issue on appeal concerned the quantity of butanediol involved and the legal consequences of its purity. The applicants argued that the trial judge erred by directing the jury that the butanediol was a "mixture" for the purposes of the Controlled Substances Regulations 2011 (SA), thereby triggering a presumption of trafficking.

The court was required to determine whether the trial judge was correct in ruling that the butanediol seized, which was of high purity (approximately 95%), constituted a "mixture" as defined by the regulations, or if it was in its "pure" form. The distinction was critical because the regulations prescribe a large commercial quantity for butanediol in its mixed form, but not for its pure form. If the butanediol was pure, the applicants could only have been convicted of the lesser offence of attempted trafficking.

The court reasoned that the evidence did not establish that the butanediol was a mixture. While it contained minor impurities consistent with manufacturing and degradation, it was not otherwise adulterated. The trial judge's direction to the jury on the premise that it was a mixture, without leaving the factual question of its purity to the jury, constituted an error of law. Consequently, the court allowed the appeal, quashed the convictions for trafficking a large commercial quantity, and substituted verdicts of guilty for attempted trafficking in butanediol.