Re Brennan; Ex parte Muldowney

This matter concerned an application for a writ of prohibition brought by Muldowney against Brennan, a magistrate. Muldowney sought to prohibit Brennan from proceeding with a committal hearing for an offence under the *Crimes Act 1914* (Cth). The core of the dispute revolved around the admissibility of evidence obtained by Commonwealth police officers.

The central legal issue before the High Court was whether evidence obtained by Commonwealth police officers in contravention of a statutory provision, specifically section 271 of the *Customs Act 1901* (Cth), was admissible in committal proceedings. Section 271 of the *Customs Act* prescribed the manner in which searches were to be conducted, and the evidence in question was obtained in breach of these requirements.

Mason CJ held that the admissibility of evidence obtained in contravention of a statutory provision was a matter for the court to determine, and that the court possessed a discretion to exclude such evidence. His Honour reasoned that while the common law did not automatically render inadmissible evidence obtained unlawfully, the court's power to control its proceedings and ensure fairness allowed for the exclusion of evidence where its admission would be an abuse of process or otherwise unfair. The Court considered the nature of the contravention, the importance of the statutory provision, and the potential prejudice to the accused when exercising this discretion.