R v Abdulle, 2016 ABCA 5:
 The rule in Browne v Dunn requires counsel to put a matter to a witness if counsel intends to present contradictory evidence on that matter through a later witness: Werkman at para 7. Where the rule is breached, the trial judge may take the failure into account in assessing credibility: Werkman at para 9. The failure to cross-examine must relate to matters of substance. Where the evidence is of little significance in the overall context of the case, the failure to cross-examine should have no effect on the assessment of credibility: R v Paris (2000), 2000 CanLII 17031 (ON CA), 138 OAC 287 at para 23. Absent an error of law or a misapprehension of the evidence, a trial judge's assessment of credibility is, however, entitled to deference.
 The appellant advances two errors by the trial judge in the application of the rule in Browne v Dunn. First, he says the trial judge erred in applying the rule to insignificant or minor details. The trial judge found that the failure to cross-examine with respect to alcohol was a detail not warranting a strict Browne v Dunn application, yet he said he would use it in assessing credibility. Similarly, the trial judge said he would not strictly consider the failure to cross-examine with respect to marijuana from a Browne v Dunn perspective, yet he did consider it from a credibility perspective.
 While a trial judge's characterization of a matter as significant or insignificant is entitled to deference, here the trial judge appears to have concluded that the matters were details not warranting a "strict" application of the rule yet he nevertheless applied the remedy for breach of the rule in assessing credibility. In our view, the trial judge erred in this approach. We do not understand what the trial judge meant by his reference to a "strict" application of the rule. The rule is either engaged or it is not engaged. If it is engaged, in the sense that there is a failure to cross-examine on a matter of sufficient substance, then a remedy is available. On the other hand, if the matter is minor or of insufficient significance, the rule is not engaged and no remedy is necessary.
 The second error advanced by the appellant concerns trial fairness. During argument, the trial judge asked defence counsel to comment on five matters which the trial judge thought might engage the rule in Browne v Dunn. As to some matters, counsel argued that the matter was an unimportant detail. In one case, counsel said he had put the matter to the witness but perhaps not directly enough. On another, counsel agreed that the matter was not put to the witness and that the appellant's testimony on that matter should be disregarded. Most of these matters were addressed by the trial judge in his reasons.
 However, the trial judge did not raise the issue of whether defence counsel had cross-examined the complainants on the appellant's assertion that only one person, Abdi, was involved in the robberies. In his reasons, the trial judge found that this matter had not been put to the complainants and the failure to do so was a breach of the rule resulting in significantly less weight being given to the appellant's evidence. The appellant argues that finding a breach of the rule without providing counsel the opportunity to address the issue compromised trial fairness.
 Moreover, the appellant argues the trial judge erred in applying the rule because the matter was raised in cross-examination. Lu gave the following evidence in cross-examination:
Q: ... do you recall if your cell phone and Emilio's cell phone were taken by the same individual or by two separate individuals?
A: I don't recall.
Calcines gave the following evidence in cross examination:
Q: Do you know which one of the two individuals it was that produced the knife?
Q: And then they take your cell phones, and by your cell phones, I mean your cell phone and Jimmy's cell phone?
Q: And do you recall who took the phones?
A: It was - one guy for each of us, but I don't remember which guy was attacking me and which guy was attacking Jimmy.
 Had the trial judge given defence counsel the opportunity to address this issue, counsel may have convinced the trial judge that the matter was raised, albeit in a rather indirect way, and that there was no breach of the rule as it related to that matter. Although we cannot speculate on the effect counsel's submissions might have had on the trial judge's finding on this issue, it is clear that the trial judge placed significantly less weight on the appellant's evidence as a result of the perceived breach.
 The Crown argues that the failure to put to the complainants the assertion that an argument took place between Abdi and Calcines, which precipitated the assault and robbery, may have been enough to erode the appellant's credibility beyond repair without any consideration of the other breaches of the rule. This is, in essence, a submission that the failure to afford counsel the opportunity to address this significant issue in argument amounts to harmless error. We are unable to agree with that submission. We do not know whether the trial judge would have come to the same conclusion concerning the appellant's credibility absent this error.
 The errors in applying a Browne v Dunn remedy to minor details and in not affording counsel an opportunity to respond to an issue of significance to the trial judge's findings on credibility, lead to the conclusion that a new trial is required.
Of the Law Societies of Upper Canada and Nunavut