R v Keenan

The High Court of Australia considered the appeal of R v Keenan, where the appellant had been convicted of murder. The central dispute concerned the admissibility of certain evidence obtained during police interviews and the proper application of the exclusionary rule in relation to that evidence.

The High Court was required to determine whether the evidence obtained from the appellant during police interviews, which were conducted after he had been cautioned but before he was formally charged, was admissible. Specifically, the Court had to consider whether the evidence was obtained in contravention of the appellant's rights and, if so, whether the exclusionary rule, which permits the exclusion of improperly obtained evidence, should have been applied by the trial judge. The Court also considered the principles governing the exercise of discretion to exclude evidence that, while technically admissible, might be unfairly prejudicial to the accused.

The Court reasoned that the admissibility of evidence obtained during police interviews is governed by both statutory provisions and common law principles. While the police had cautioned the appellant, the Court examined whether the circumstances of the interviews, including the length and nature of questioning, might have rendered the subsequent admissions unreliable or unfairly obtained. The High Court affirmed the principle that courts have a discretion to exclude evidence if its probative value is outweighed by the danger of unfair prejudice to the accused, or if the evidence was obtained improperly. The Court analysed the trial judge's exercise of discretion in admitting the evidence, considering whether that discretion had been misapplied.

Ultimately, the High Court allowed the appeal, quashed the conviction, and ordered a new trial. The Court found that the trial judge had erred in admitting the evidence in question, as its prejudicial effect outweighed its probative value and it had been obtained in circumstances that raised concerns about fairness.