O'Brien v The Queen

In *O'Brien v The Queen*, the High Court of Australia considered an appeal by the applicant, O'Brien, against his conviction for murder. The dispute centred on the admissibility of certain evidence during his trial.

The primary legal issue before the High Court was whether the trial judge had erred in admitting evidence of the applicant's prior convictions and prior bad character. This involved determining whether such evidence was relevant to the issues in the trial and, if so, whether its probative value outweighed its prejudicial effect, in accordance with the principles governing the admission of such evidence in criminal proceedings.

The High Court held that the admission of the evidence of prior convictions and bad character was an error. Their Honours reasoned that the evidence was not relevant to any issue in the trial and was introduced in a manner that was likely to prejudice the jury against the applicant. The court applied the principles established in cases such as *IMM v The Queen* and *Pfennig v The Queen*, which require a high degree of relevance and a careful balancing of probative value against prejudicial effect before such evidence can be admitted.

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