There was no authority to suggest that expert evidence was receivable to explain the testimony of a prosecution witness other than where an abnormality of the mind existed. As a matter of principle the credibility of a witness was a matter for the jury to assess and admitting expert evidence on the issue of credibility would be to usurp the function of the jury.

CA (Otton LJ, Douglas Brown J, Judge Stephens QC)

20/12/2000