Towards the Principled Reception of Expert Evidence of Witness Credibility in Criminal Trials

Abstract

R v MacKenney and Pinfold (1981) has for some 20 years been a well-known authority on the admissibility of expert evidence, more particularly with regard to expert evidence of witness credibility. In that case, the trial judge refused to receive expert evidence challenging a prosecution witness's credibility proffered at trial on behalf of the accused, a decision upheld on appeal. Belatedly, on a recent reference from the Criminal Cases Review Commission, the Court of Appeal has quashed the appellants' convictions, prompting reconsideration of the original determination of inadmissibility. Notwithstanding the Court of Appeal's apparent change of heart, however, it is submitted that the principles rehearsed in R v Pinfold and MacKenney (2003) are entirely consistent with the ‘helpfulness’ test of admissibility adumbrated in Turner, and that the court's latest remarks on this topic serve chiefly to clarify and reinforce established legal orthodoxy.