Kizon v The Queen; Mansfield v The Queen

In *Kizon v The Queen* and *Mansfield v The Queen*, the High Court of Australia considered appeals against convictions for conspiracy to import a commercial quantity of heroin. The central dispute revolved around the admissibility of evidence obtained from intercepted communications, specifically whether the prosecution had discharged its onus to prove that the intercepted material was not unlawfully obtained.

The High Court was required to determine whether the trial judge had erred in admitting the intercepted communications into evidence, notwithstanding the defence's challenge to their lawful acquisition. This involved considering the scope of the prosecution's obligation to prove compliance with statutory requirements for lawful interception and the appropriate standard of proof to be applied in such circumstances.

The Court reasoned that the onus rested on the prosecution to establish, on the balance of probabilities, that the interceptions were lawfully made. This required demonstrating adherence to the relevant legislative framework governing telecommunications interception. The High Court found that the prosecution had failed to discharge this onus, as there was insufficient evidence to establish that the authorisations for the interceptions were validly made. Consequently, the intercepted communications should not have been admitted into evidence.

The High Court allowed the appeals, quashed the convictions, and ordered that the Crown be permitted to have a new trial.