R v Chai

The High Court of Australia considered an appeal by the Crown against a decision of the Court of Appeal of the Supreme Court of New South Wales, which had allowed an appeal by the respondent, Mr Chai, against his conviction for the offence of conspiracy to import a commercial quantity of a prohibited drug. The central dispute concerned the admissibility of certain evidence obtained by police surveillance.

The primary legal issue before the High Court was whether the evidence obtained through covert surveillance, specifically audio recordings made from a listening device, was admissible in circumstances where the police had not obtained a warrant authorising the use of that device. This raised questions about the scope of the common law power to conduct such surveillance and the application of statutory provisions governing the use of listening devices.

The High Court, by majority, held that the common law did not confer a power on police to use listening devices without a warrant. The Court reasoned that the common law, in the absence of statutory authorisation, did not permit such an intrusion into privacy. The use of listening devices was considered to be a significant interference with individual liberty and privacy, and any such power must be clearly and unequivocally conferred by legislation. The Court found that the relevant legislation did not grant such a broad power and that the evidence obtained was therefore inadmissible.

Consequently, the High Court dismissed the Crown's appeal, upholding the decision of the Court of Appeal of New South Wales. The conviction of Mr Chai was accordingly quashed.