The High Court has decided a special case and upheld the validity of s 18 of the Criminal Law Amendment Act 1945 (Qld), which relates to continued detention of child sex offenders after the expiry of sentence, ‘at her Majesty’s pleasure’, on the grounds that the ‘offender is incapable of exercising proper control over the offender’s sexual instincts’. Section 18(4) was recently amended to transfer the power to make an application for indefinite detention from the Governor to the Attorney-General. Pollentine and Radan were both convicted in 1984 of child sex offences, and have both been detained under s 18.

The Court unanimously rejected the plaintiffs’ contention that s 18 was invalid because it contravened ch III of the Australian Constitution and specifically the Kable principle. As the plurality noted at [42], the Kable principle prevents State Parliaments from conferring on State Courts powers that are repugnant to or incompatible with their exercise of Commonwealth judicial power, in the sense of compromising their institutional integrity as part of the Australian constitutional system. The plurality rejected the plaintiffs’ first argument — that an indefinite detention order delegates to the Executive the power to determine an offender’s incarceration — on the grounds, first, that a sentencing court must decide whether s 18 applies in a particular case, and then determine whether to make an indefinite detention order, at neither point being bound by the Executive decision (at [44]) and secondly, the decision to release an indefinitely detained person is not solely at the discretion of the Executive, but requires medical opinion indicating a reduced risk of reoffending: the court has thus not delegated its power fix the extent of punishment, because continued detention depends upon community risk and is not further punishment for the original offence (at [45]). The plurality also rejected the plaintiffs’ argument that because the criteria the court uses for ordering indefinite detention are different to those the Executive applies when considering releasing a person, the latter is a political decision cloaked ‘in the neutral colours of judicial action’ (Mistretta v United States [1989] USSC 9). The plurality held that the Executive decision is made by a political arm of government, does not in any way appear as if it were made by a court, and is subject to judicial review: [47]. Finally, the plurality rejected the argument that the validity of the provision required safeguards were needed to protect the institutional integrity of the court: the mere fact that these decisions were made by the Executive and not a court (as in Fardon v Attorney-General (Qld) [2004] HCA 46) did not show that s 18 or any other feature of the Act contravened the Kable principle. Gageler J issued a separate judgment likewise concluding that s 18 was not invalid.