Lord Bingham had this to say in “The Judge as Juror; the Judicial Determination of Factual Issues (Current Legal Problems 38) Bingham J (writing extra-judicially),
“the main tests needed to determine whether a witness is lying or not are, I think, the following, although their relative importance will vary widely from case to case:
(a) The consistency of the witness’s evidence with what is agreed or clearly shown by other evidence, to have occurred;
(b) The internal consistency of the witness’s evidence;
(c) Consistency with what the witness has said or deposed on other occasions;
(d) The credit of the witness in relation to matters not germane to the litigation;
(e) The demeanour of the witness.”
This passage was cited with approval in Mansion Estates Ltd v Hayre & Co  EWHC 96 (CH).