R v Cao

The appeal concerned a sentence imposed on the appellant, Mr Cao, who was convicted of trafficking in a controlled drug, namely methamphetamine or heroin, contrary to section 32 of the Controlled Substances Act 1984 (SA). Mr Cao's co-offender had pleaded guilty to trafficking in a commercial quantity of heroin. At the time of the offence, Mr Cao was on parole for a prior conviction in 2006, with an unexpired sentence balance of two years, two months, and five days. The sentencing judge imposed a seven-year term of imprisonment, to be served cumulatively upon the unexpired balance, with a reduction for time already served in custody. This resulted in a total head sentence of eight years, eight months, and sixteen days, with a non-parole period of six years, six months, and eleven days.

The central issue on appeal was whether the sentence imposed on Mr Cao was manifestly excessive. Specifically, the court was asked to consider whether the sentencing judge had erred by not being guided by historical amendments to section 32 of the Controlled Substances Act 1984 (SA), which had reduced the maximum penalty for the offence from 25 years to 10 years imprisonment. Further questions arose regarding the sentencing judge's application of the parity principle between co-offenders, the desirability of the same judge sentencing both Mr Cao and his co-offender, and whether the sentencing judge had erroneously treated Mr Cao's offence as involving a commercial quantity of the drug.

The Full Court of the Supreme Court of South Australia held that the sentencing judge was correct not to be guided by historical versions of the Act. The court found no error in the application of the parity principle, nor in the decision for the same judge to sentence both offenders. Furthermore, the court determined that there was no basis to conclude that the sentencing judge had mistakenly sentenced Mr Cao as if his offence involved a commercial quantity of a controlled drug. Consequently, the appeal against sentence was dismissed.