It would have been possible for Parliament in enacting (or later amending) the DPCS Act to create a hierarchy of trafficking offences based not on the quantity of the drug trafficked but on the harmfulness of the drug. Parliament might, for example, have adopted a three-level hierarchy of the kind which was in 1981, and is still, in force in both the United Kingdom and New Zealand ... (Some Australian courts have developed a hierarchy of their own, with drugs of dependence being classified as 'high', 'medium' or 'low' according to the nature and extent of the harm caused (See eg R v Darwell (1997) 94 A Crim R 35 at 40; R v Budiman (1998) 102 A Crim R 411 at 416, and the cases there cited.). Had such a legislative scheme been implemented, the gradation in maximum penalties would then have been fixed according to harmfulness, not quantity.
The DPCS Act employed just such a harm-based hierarchy in relation to poisons and controlled substances. There are no fewer than nine separate schedules of poisons, and a further category of 'regulated poisons'. The provisions of the Act regulate the manufacture, use, sale and supply of poisons. How those provisions apply to a particular poison depends on the schedule in which the particular poison is listed. The more powerful/dangerous the poison, the more restrictive the applicable regulations.
But no such harm-based hierarchy was adopted for the purposes of classifying trafficking offences. Were such a ranking of drugs of dependence to be attempted, the obvious starting-point would be the nature and extent of the dependency created by each drug. Relevant measures would include: the likelihood of a user becoming dependent; the speed with which such dependency typically becomes established; and the degree of difficulty involved in breaking that dependency. Across the very large number of drugs of dependence specified in Sch 11, there would no doubt be considerable variation in these characteristics.
Another factor which would affect such a ranking of drugs would be the physical and psychological harm caused to the user of each drug. Once again, there would be considerable variation from one drug of dependence to another. Moreover, any comparative evaluation of harmfulness on this basis will only be as good as the scientific information available at the time it is made. To remain valid, these harm assessments would need to be regularly reviewed and updated in the light of new research.
A third factor relevant to the ranking would be the social effects of dependency on the particular drug: the effect of dependency on the user's relationships with others; the propensity of users to engage in acts of violence while under the influence of the drug; and the likelihood of users having to engage in criminal activity in order to support the drug habit.
Reference to these different dimensions of harmfulness underlines how different the trafficking provisions in the DPCS Act would have needed to be if Parliament had intended to rank - and punish - trafficking offences by reference to the relative harmfulness of the drug trafficked. Crucially for present purposes, that is not the ranking which the Act adopts for these offences. By contrast, the offence of possessing for personal use a small quantity of cannabis has been viewed by the legislature as warranting a lower maximum penalty, evidently because of an assessment that cannabis is less harmful than other drugs: DPCS Act s 73(1)(a) ...
If the seriousness of a drug trafficking offence is to be judged by reference to the harmfulness of the drug in question, that will involve a significant policy change, of the kind which the legislature alone can make. Just how significant that change would be is illustrated by the equivalent legislation in the United Kingdom and New Zealand. Not only do those jurisdictions employ a harm-based classification of drugs, but the critical questions of classification and re-classification are - properly, in our view - the province of expert advisory committees and the ministers they advise, not of judges and magistrates.