Duncan v Independent Commission Against Corruption

The case of *Duncan v Independent Commission Against Corruption* concerned a challenge to the validity of Part 13 of Schedule 4 to the *Independent Commission Against Corruption Act 1988* (NSW). The applicant argued that this provision, inserted after the High Court's decision in *Independent Commission Against Corruption v Cunneen* [2015] HCA 14, was invalid. The *Cunneen* decision had narrowed the definition of "corrupt conduct" under the Act, potentially invalidating past actions of the Independent Commission Against Corruption (ICAC). Part 13 was enacted to retrospectively validate such acts.

The central legal issues before the High Court were whether Part 13 of Schedule 4 of the ICAC Act was validly enacted. Specifically, the applicant contended that the provisions did not, as a matter of construction, deem the conduct in question to be "corrupt conduct" and therefore did not validate invalid acts. Instead, the applicant argued, Part 13 improperly directed courts to treat as valid acts that remained invalid, thereby undermining the institutional integrity of the Supreme Court of New South Wales contrary to the principle in *Kable v Director of Public Prosecutions (NSW)*, and infringing upon the Supreme Court's power to grant relief for jurisdictional error, as established in *Kirk v Industrial Court (NSW)*.

The High Court dismissed the applicant's challenge, finding his construction of Part 13 to be implausible and unsustainable on a fair reading of its provisions. The Court held that Part 13 operated to amend the definition of "corrupt conduct" for acts occurring before 15 April 2015, effectively changing the substantive law. Clauses 34 and 35 were interpreted as deeming acts done by the ICAC to be valid to the extent they would have been valid if the definition of corrupt conduct had included conduct that adversely affected the efficacy, but not the probity, of official functions. The Court found that this retrospective validation of the ICAC's actions did not contravene the principles in *Kable* or *Kirk*, as it did not usurp the jurisdiction of the Supreme Court but rather clarified the legal position of the ICAC and affected persons.

The High Court ordered that so much of the proceeding pending in the Court of Appeal of the Supreme Court of New South Wales as concerned specific grounds and prayers of the applicant's notice of appeal be dismissed, and that the applicant pay the respondent's costs.