Farrell v The Queen

The High Court of Australia heard an appeal by the appellant, Farrell, against his convictions for various offences. The dispute centred on the admissibility and use of expert psychiatric evidence concerning the complainant's reliability as a witness, and whether the trial judge's rulings and directions on this evidence amounted to a misdirection that deprived the appellant of a fair trial.

The legal issues before the Court were whether expert evidence disclosing a mental disability likely to bear on the reliability of a complainant's evidence was admissible, and whether the jury was adequately directed on the weight to be given to such expert evidence. Specifically, the Court considered whether the possibility of memory impairment due to alcohol and substance abuse, or knowledge of anti-social personality disorder, fell within the experience of ordinary persons, and if not, whether the exclusion of such expert testimony and subsequent jury directions constituted a misdirection occasioning a mistrial.

The Court reasoned that the trial judge erred in excluding expert psychiatric evidence that could have shed light on the complainant's reliability, particularly given the crucial nature of the complainant's testimony to the Crown's case. The Court found that the potential impact of alcohol and substance abuse on memory, and the characteristics of an anti-social personality disorder, were not matters within the ordinary experience of a jury. Therefore, expert evidence on these matters was admissible and vital for the defence. The judge's subsequent directions to the jury on the use of any admitted expert evidence were also found to be inadequate, effectively diminishing the impact of potentially exculpatory evidence and thereby depriving the appellant of a fair chance of acquittal.

The appeal was allowed, the orders of the Court of Criminal Appeal of Tasmania were set aside, and in lieu thereof, the appeal to that court was allowed, the convictions were quashed, and a new trial was ordered on the relevant counts.