“52. In a perfect world, any ground for doubting the evidence of a witness ought to be put to him, and a judge should only rely on a ground for disbelieving a witness which that witness has had an opportunity of explaining. However, the world is not perfect, and, while both points remain ideals which should always be in the minds of cross-examiners and trial judges, they cannot be absolute requirements in every case. Even in a very full trial, it may often be disproportionate and unrealistic to expect a cross-examiner to put every possible reason for disbelieving a witness to that witness, especially in a complex case, and it may be particularly difficult to do so in a case such as this, where the Judge sensibly rationed the time for cross-examination and the witness concerned needed an interpreter. Once it is accepted that not every point may be put, it is inevitable that there will be cases where a point which strikes the judge as a significant reason for disbelieving some evidence when he comes to give judgment, has not been put to the witness who gave it. 53. Mr Parker relies on a general rule, namely that “it will not do to impeach the credibility of a witness upon a matter on which he has not had any opportunity of giving an explanation by reason of there having been no suggestion whatever in the course of the case that his story is not accepted”, as Lord Herschell LC put it in Browne v Dunn (1893) 6 R 67, 71. In other words, where it is not made clear during (or before) a trial that the evidence, or a significant aspect of the evidence, of a witness (especially if he is a party in the proceedings) is challenged as inaccurate, it is not appropriate, at least in the absence of further relevant facts, for the evidence then to be challenged in closing speeches or in the subsequent judgment. A relatively recent example of the application of this rule by the English Court of Appeal can be found in Markem Corpn v Zipher Ltd[2005] RPC 31 . 54. … It appears to the Board that an appellate court’s decision whether to uphold a trial judge’s decision to reject a witness’s evidence on grounds which were not put to the witness must depend on the facts of the particular case. Ultimately, it must turn on the question whether the trial, viewed overall, was fair bearing in mind that the relevant issue was decided on the basis that a witness was disbelieved on grounds which were not put to him. 55. At a relatively high level of generality, in such a case an appellate court should have in mind two conflicting principles: the need for finality and minimising costs in litigation, on the one hand, and the even more important requirement of a fair trial, on the other. Specific factors to be taken into account would include the importance of the relevant issue both absolutely and in the context of the case; the closeness of the grounds to the points which were put to the witness; the reasonableness of the grounds not having been put, including the amount of time available for cross-examination and the amount of material to be put to the witness; whether the ground had been raised or touched on in speeches to the court, witness statements or other relevant places; and, in some cases, the plausibility of the notion that the witness might have satisfactorily answered the grounds.”
“… where a witness' honesty is to be challenged, it will always be best if that is explicitly put to the witness. There can then be no doubt that honesty is in issue. But what ultimately matters is that the witness has had fair notice of a challenge to his or her honesty and an opportunity to deal with it. It may be that in a particular context a cross-examination which does not use the words "dishonest" or "lying" will give a witness fair warning. That will be a matter for the trial judge to decide. …”