Mackay v The Queen

Mackay appealed his conviction for murder in the Supreme Court of Queensland. The central issue on appeal concerned the admissibility of certain evidence obtained from the appellant, specifically a confession made to police. The High Court of Australia was required to determine whether this confession was lawfully obtained, and if not, whether its admission at trial had occasioned a miscarriage of justice.

The High Court considered the admissibility of the confession under the common law, particularly in light of the appellant's circumstances at the time of his questioning. The court examined whether the confession was voluntary, meaning it was not induced by threats, promises, or other improper pressure. Furthermore, the court had to assess whether the police had acted unlawfully in obtaining the confession, considering the relevant provisions of Queensland law concerning the questioning of suspects.

The majority of the High Court held that the confession was inadmissible because it was obtained in circumstances that rendered it involuntary. The court applied the principle that a confession must be the voluntary act of the accused to be admissible. Because the confession was deemed inadmissible, the court then considered whether its admission at trial had led to a miscarriage of justice. The majority concluded that the admission of the confession was a material error that had prejudiced the appellant's case, leading to an unsafe conviction.

Consequently, the High Court allowed the appeal, quashed the conviction, and ordered a new trial.