The case of Excelerate Technology Ltd -v- Cumberbatch [2015] EWHC B1 Mercantile was looked at in an earlier post in relation to the judge’s observations about the costs budget*. It did, however, contain important observations about the way in which judges assess the credibility of witnesses.


There is an excellent post by Janna Purdie on the Lexis Nexis Dispute Resolution Blog discussing this case in relation to the credibility of witnesses.


HH Simon Brown QC reviewed the guidance given to judges in relation to assessing credibility.

  1. This is essentially a case where credibility-the credibility of the First Defendant and Mr Osmond in particular-is crucial. The most compendious judicial statement on this is be found in the dissenting speech of Lord Pearce in the House of Lords in Onassis v Vergottis [1968] 2 Lloyds Rep 403 at p 431:

Credibility’ involves wider problems than mere ‘demeanour’ which is mostly concerned with whether the witness appears to be telling the truth as he now believes it to be. Credibility covers the following problems. First, is the witness a truthful or untruthful person? Secondly, is he, though a truthful person telling something less than the truth on this issue, or though an untruthful person, telling the truth on this issue? Thirdly, though he is a truthful person telling the truth as he sees it, did he register the intentions of the conversation correctly and, if so has his memory correctly retained them? Also, has his recollection been subsequently altered by unconscious bias or wishful thinking or by over much discussion of it with others? Witnesses, especially those who are emotional, who think that they are morally in the right, tend very easily and unconsciously to conjure up a legal right that did not exist. It is a truism, often used in accident cases, that with every day that passes the memory becomes fainter and the imagination becomes more active. For that reason a witness, however honest, rarely persuades a Judge that his present recollection is preferable to that which was taken down in writing immediately after the accident occurred. Therefore, contemporary documents are always of the utmost importance. And lastly, although the honest witness believes he heard or saw this or that, is it so improbable that it is on balance more likely that he was mistaken? On this point it is essential that the balance of probability is put correctly into the scales in weighing the credibility of a witness. And motive is one aspect of probability. All these problems compendiously are entailed when a Judge assesses the credibility of a witness; they are all part of one judicial process. And in the process contemporary documents and admitted or incontrovertible facts and probabilities must play their proper part.”

This is amplified by Lord Goff in Armagas Ltd v. Mundogas S.A. (The Ocean Frost), [1985] 1 Lloyd’s Rep. 1, p. 57:

“Speaking from my own experience, I have found it essential in cases of fraud, when considering the credibility of witnesses, always to test their veracity by reference to the objective facts proved independently of their testimony, in particular by reference to the documents in the case, and also to pay particular regard to their motives and to the overall probabilities. It is frequently very difficult to tell whether a witness is telling the truth or not; and where there is a conflict of evidence such as there was in the present case, reference to the objective facts and documents, to the witnesses’ motives, and to the overall probabilities, can be of very great assistance to a Judge in ascertaining the truth.” [emphases added].

  1. The absence of evidence can be as significant as the presence of it. Arden LJ in Wetton (as Liquidator of Mumtaz Properties) v. Ahmed and others[2011] EWCA Civ. 61 stated:

11. By the end of the judgment, it is clear that what has impressed the judge most in his task of fact-finding was the absence, rather than the presence, of contemporary documentation or other independent oral evidence to confirm the oral evidence of the respondents to the proceedings.12. There are many situations in which the court is asked to assess the credibility of witnesses from their oral evidence, that is to say, to weigh up their evidence to see whether it is reliable. Witness choice is an essential part of the function of a trial judge and he or she has to decide whose evidence, and how much evidence, to accept. This task is not to be carried out merely by reference to the impression that a witness made giving evidence in the witness box. It is not solely a matter of body language or the tone of voice or other factors that might generally be called the ‘demeanour’ of a witness. The judge should consider what other independent evidence would be available to support the witness. Such evidence would generally be documentary but it could be other oral evidence, for example, if the issue was whether a defendant was an employee, the judge would naturally consider whether there were any PAYE records or evidence, such as evidence in texts or e-mails, in which the defendant seeks or is given instructions as to how he should carry out work. This may be particularly important in cases where the witness is from a culture or way of life with which the judge may not be familiar. These situations can present particular dangers and difficulties to a judge.

14. In my judgment, contemporaneous written documentation is of the very greatest importance in assessing credibility. Moreover, it can be significant not only where it is present and the oral evidence can then be checked against it. It can also be significant if written documentation is absent. For instance, if the judge is satisfied that certain contemporaneous documentation is likely to have existed were the oral evidence correct, and that the party adducing oral evidence is responsible for its non-production, then the documentation may be conspicuous by its absence and the judge may be able to draw inferences from its absence. [emphasis added].

The inferences that the judge drew from the witnesses in that case are summarised in Janna’s article.


I have observed before that many of the important points of principle relating to the credibility of witnesses can be found in judgments of Simon Brown QC most markedly in Piper -v- Hales [2013] EWHC B1 (QB)

  1. The guidance about how courts approach this is given in the extra-judicial writing of the lateLord Bingham of Cornhill approved by the courts is apposite. In “The Judge as Juror: The Judicial Determination of Factual Issues” published in “The Business of Judging”, Oxford 2000, reprinted from Current Legal Problems, vol 38, 1985 p 1-27, he wrote:

“. . . Faced with a conflict of evidence on an issue substantially effecting the outcome of an action, often knowing that a decision this way or that will have momentous consequences on the parties’ lives or fortunes, how can and should the judge set about his task of resolving it ? How is he to resolve which witness is honest and which dishonest, which reliable and which unreliable? . . .

The normal first step in resolving issues of primary fact is, I feel sure, to add to what is common ground between the parties (which the pleadings in the action should have identified, but often do not) such facts as are shown to be incontrovertible. In many cases, letters or minutes written well before there was any breath of dispute between the parties may throw a very clear light on their knowledge and intentions at a particular time. In other cases, evidence of tyre marks, debris or where vehicles ended up may be crucial. To attach importance to matters such as these, which are independent of human recollection, is so obvious and standard a practice, and in some cases so inevitable, that no prolonged discussion is called for. It is nonetheless worth bearing in mind, when vexatious conflicts of oral testimony arise, that these fall to be judged against the background not only of what the parties agree to have happened but also of what plainly did happen, even though the parties do not agree.


This issue is also discussed in a number of other posts.

1. Litigators must know about credibility.

2. Witness Statements and Witness Evidence: More about Credibility.

3. Which Witness will be believed?Is it all a lottery?

4. The witnesses say the other side is lying: What does the judge do?

5. Assessing the reliability of witnesses: How does the judge decide?

6.  Which witness is going to be believed? A High Court case.

7. The Mitchell case and witness evidence: credibility, strong views and reliability.

8. Witness statements and witness credibility: getting back to basics


* That single post on costs got twice as many readers the day of publication that the posts about the Gordon Ramsey and Rihanna cases combined. (Demonstrating that lawyers are much more concerned about costs than celebrities?)