The post yesterday on witness credibility in the case of Frenkel v Lyampert & Ors [2017] EWHC 2223 (Ch) referred to a passage in the earlier case of EPI Environmental Technologies Inc v Symphony Plastic Technologies plc (Practice Note) [2005] 1 WLR 3456   This is guidance given pre-Gestmin, but given the judgment in Frenkel it is clearly relevant to the way in which the courts assess credibility of lay and expert witnesses alike.



Peter Smith J was considering breach of confidentiality agreements in relation to a substance that made plastic bags biodegradable.


    1. Credibility in this case is important both as regards the non-expert and expert witnesses. My analysis of that evidence is set out in the confidential part of the judgment.

    2. A significant point from EPI’s point of view is the lack of documentation showing how Symphony created BD92384.

    3. Both parties have reminded me of some well-known judicial observations designed to assist trial judges in how they arrive at factual conclusions.

    4. First, EPI referred me to Plowman J in Suhner & Co AG –v- Transradio Ltd [1967] RPC 329 at 333, where he said this:-

A great deal of the defendants’ evidence seems to me to be really beside the point, first of all, because the confidential nature of the document is not dependent on whether the information which it contains is available elsewhere; but, on the question of whether it contains useful information which has been compiled by the plaintiffs for a particular purpose and, if it does contain such information and if it has been compiled and handed over to the defendants for a particular purpose, then, as I understand the law, that document is confidential and the defendants are not entitled to use it for another purpose”.

    1. In their closing submissions EPI referred me to the (once again well known) observations of Robert Goff LJ in The Ocean Frost [1985] 1 LL Rep 1 at page 57, as follows:-

“Furthermore it is implicit in the statement of Lord MacMillan in Powell v. Streatham Manor Nursing Home at p. 256 that the probabilities and possibilities of the case may be such as to impel an appellate Court to depart from the opinion of the trial Judge formed upon his assessment of witnesses whom he has seen and heard in the witness box. 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. I have been driven to the conclusion that the Judge did not pay sufficient regard to these matters in making his findings of fact in the present case”.

    1. Not to be out done Symphony in its closing submissions reminded me of the observations of Simon Brown LJ in Biggar –v- London Borough of Havering [2001] EWCA Civ 411:-

15. The correct approach to the standard of proof and the nature of proof required in the case of grave allegations is to be found in the speech of Lord Nicholls of Birkenhead in In re H (Minors) [1996] AC 563 at 586-587:

“The balance of probability standard means that the court is satisfied an event occurred if the court considers that, on the evidence, the occurrence of the event was more likely than not. When assessing the probabilities the court will have in mind as a factor, to whatever extent is appropriate in the particular case, that the more serious the allegation the less likely it is that the event occurred and, hence, the stronger should be the evidence before the court concludes that the allegation is established on the balance of probability. Fraud is usually less likely than negligence. Deliberate physical injury is usually less likely than accidental physical injury. A stepfather is usually less likely to have repeatedly raped and had non-consensual oral sex with his under age stepdaughter than on some occasion to have lost his temper and slapped her. Built into the preponderance of probability standard is a generous degree of flexibility in respect of the seriousness of the allegation.

Although the result is much the same, this does not mean that where a serious allegation is in issue the standard of proof required is higher. It means only that the inherent probability or improbability of an event is itself a matter to be taken into account when weighing the probabilities and deciding whether, on balance, the event occurred. The more improbable the event, the stronger must be the evidence it did occur before, on the balance of probability, its occurrence will be established. Ungoed-Thomas J expressed this neatly in In re Dellow’s Will Trusts [1964] 1 WLR 451,455: ‘The more serious the allegation the more cogent is the evidence required to overcome the unlikelihood of what is alleged and thus to prove it.’

This substantially accords with the approach adopted in authorities such as the well known judgment of Morris LJ of Hornal v Neuberger Products Ltd [1957] 1 QB 247, 266. This approach also provides a means by which the balance of probabilities standard can accommodate one’s instinctive feeling that even in civil proceedings a court should be more sure before finding serious allegations proved than when deciding less serious or trivial matters.

No doubt it is this feeling which prompts judicial comment from time to time that grave issues call for proof to a standard higher than the preponderance of probability.”

    1. Symphony reinforced this by references to two decisions of Laddie J, namely CMI Centres for Medical Innovation, Dr Christoph von Keudel [1998] EWHC PAT 308 at 49 – 50 and Ocular Sciences [1997] RPC 289, 359. Those judgments respectively address allegations of dishonesty in breach of confidence cases and the caution against allowing breach of confidence actions to be used as a method of trade protection, as opposed to genuine actions for infringements of confidential information.

    2. I have borne all of these matters in my mind when assessing the evidence and the result of my assessment is set out in the confidential part of this judgment.

    3. I add a few of my own precautions.

i) First, it is essential to evaluate a witness’s performance in the light of the entirety of his evidence. Witnesses can make mistakes, but those mistakes do not necessarily affect other parts of their evidence.

ii) Second, witnesses can regularly lie. However, lies are themselves does not mean necessarily that the entirety of that witnesses evidence is rejected. A witness may lie in a stupid attempt to bolster a case, but the actual case nevertheless remains good irrespective of the lie. A witness may lie because the case is a lie.

iii) Third, I regard it as essential that witnesses are challenged with the other side’s case. This involves putting the case positively. This is important for a judge to enable him to assess that witness’s response to the other case orally, by reference to his or her demeanour and in the overall context of the litigation. A failure to put a point should usually disentitle the point to be taken against a witness in a closing speech. This is especially so in an era of pre prepared witness statements. A judge does not see live in chief evidence, thereby depriving the witness of presenting himself positively in his case.

  1. None of the above or the helpful assistance provided by the reported authorities is necessarily determinative. All of them provide factors to enable a judge to come to a particular conclusion about the acceptance or rejection of a particular persons evidence.

  2. I should stress also that in my view those points also are equally applicable to experts. A judge is very rarely helped by competing expert reports, which express opinions, which are not tested or not maintainable by reference to supporting material. It is not useful simply to leave the judge to find his own analysis of the reports of experts without the experts themselves being put to the test by cross examination. Finally, in the context of experts, with the CPR they have in my view acquired greater responsibilities to the court. Those responsibilities transcend their perceived obligations to the parties whom they give evidence; see Phillips & Others –v- Symes & Others [2004] EWHC 2330 (Ch).”


On taking witness statements

On witness credibility generally