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  [2016] EWHC 96 (CH).