R. v. Quansah, 2015 ONCA 237 :
 In Browne v. Dunn, Lord Herschell, L.C., explained that if a party intended to impeach a witness called by an opposite party, the party who seeks to impeach must give the witness an opportunity, while the witness is in the witness box, to provide any explanation the witness may have for the contradictory evidence: Browne v. Dunn, pp. 70-71; R. v. Henderson (1999), 134 C.C.C. (3d) 131 (Ont. C.A.), at p. 141; and R. v. McNeill (2000), 144 C.C.C. (3d) 551 (Ont. C.A.), at para. 44.
 The rule in Browne v. Dunn, as it has come to be known, reflects a confrontation principle in the context of cross-examination of a witness for a party opposed in interest on disputed factual issues. In some jurisdictions, for example in Australia, practitioners describe it as a “puttage” rule because it requires a cross-examiner to “put” to the opposing witness in cross-examination the substance of contradictory evidence to be adduced through the cross-examiner’s own witness or witnesses.
 The rule is rooted in the following considerations of fairness:
i. Fairness to the witness whose credibility is attacked:
The witness is alerted that the cross-examiner intends to impeach his or her evidence and given a chance to explain why the contradictory evidence, or any inferences to be drawn from it, should not be accepted: R. v. Dexter, 2013 ONCA 744, 313 O.A.C. 226, at para. 17; Browne v. Dunn, at pp. 70-71.
ii. Fairness to the party whose witness is impeached:
The party calling the witness has notice of the precise aspects of that witness’s testimony that are being contested so that the party can decide whether or what confirmatory evidence to call; and
iii. Fairness to the trier of fact:
Without the rule, the trier of fact would be deprived of information that might show the credibility impeachment to be unfounded and thus compromise the accuracy of the verdict.
 In addition to considerations of fairness, to afford the witness the opportunity to respond during cross-examination ensures the orderly presentation of evidence, avoids scheduling problems associated with re-attendance and lessens the risk that the trier of fact, especially a jury, may assign greater emphasis to evidence adduced later in trial proceedings than is or may be warranted.
 Failure to cross-examine a witness at all or on a specific issue tends to support an inference that the opposing party accepts the witness’s evidence in its entirety or at least on the specific point. Such implied acceptance disentitles the opposing party to challenge it later or, in a closing speech, to invite the jury to disbelieve it: R. v. Hart (1932), 23 Cr. App. R. 202 (Ct. Crim. App.), at pp. 206-207; R. v. Fenlon (1980), 71 Cr. App. R. 307 (C.A.), at pp. 313-314.
 As a rule of fairness, the rule in Browne v. Dunn is not a fixed rule. The extent of its application lies within the sound discretion of the trial judge and depends on the circumstances of each case: R. v. Paris (2000), 150 C.C.C. (3d) 162 (Ont. C.A.), leave to appeal to S.C.C. refused,  S.C.C.A. No. 124, at paras. 21-22; R. v. Giroux (2006), 207 C.C.C. (3d) 512 (Ont. C.A.), leave to appeal to S.C.C. refused,  S.C.C.A. No. 211, at para. 42.
 Compliance with the rule in Browne v. Dunn does not require that every scrap of evidence on which a party desires to contradict the witness for the opposite party be put to that witness in cross-examination. The cross-examination should confront the witness with matters of substance on which the party seeks to impeach the witness’s credibility and on which the witness has not had an opportunity of giving an explanation because there has been no suggestion whatever that the witness’s story is not accepted: Giroux, at para. 46; McNeill, at para. 45. It is only the nature of the proposed contradictory evidence and its significant aspects that need to be put to the witness: Dexter, at para. 18; R. v. Verney (1993), 87 C.C.C. (3d) 363 (Ont. C.A.), at pp. 375-376; Paris, at para. 22; and Browne v. Dunn, at pp. 70-71.
 In some cases, it may be apparent from the tenor of counsel’s cross-examination of a witness that the cross-examining party does not accept the witness’s version of events. Where the confrontation is general, known to the witness and the witness’s view on the contradictory matter is apparent, there is no need for confrontation and no unfairness to the witness in any failure to do so.
 It is worthy of reminder, however, that the requirement of cross-examination does not extend to matters beyond the observation and knowledge of the witness or to subjects upon which the witness cannot give admissible evidence.
 The potential relevance to the credibility of an accused’s testimony of the failure to cross-examine a witness for the prosecution on subjects of substance on which the accused later contradicts the witness’ testimony depends on several factors. The factors include but are not limited to:
i. the nature of the subjects on which the witness was not cross-examined;
ii. the overall tenor of the cross-examination; and
iii. the overall conduct of the defence.
See Paris, at para. 23.
 Where the subjects not touched in cross-examination but later contradicted are of little significance in the conduct of the case and the resolution of critical issues of fact, the failure to cross-examine is likely to be of little significance to an accused’s credibility. On the other hand, where a central feature of a witness’s testimony is left untouched by cross-examination, or even implicitly accepted in cross-examination, the absence of cross-examination is likely to have a more telling effect on an accused’s credibility: Paris, at para. 23.
 The confrontation principle is not violated where it is clear, in all the circumstances, that the cross-examiner intends to impeach the witness’s story: Browne v. Dunn, at p. 71. Counsel, who has cross-examined the witness on the central features in dispute, need not descend into the muck of minutiae to demonstrate compliance with the rule: Verney, at p. 376.
 Two preliminary and oft-made observations serve as my point of departure for the discussion that follows.
 First, it is too easily overlooked that the rule in Browne v. Dunn is not some ossified, inflexible rule of universal and unremitting application that condemns a cross-examiner who defaults to an evidentiary abyss. The rule is grounded in fairness, its application confined to matters of substance and very much dependent on the circumstances of the case being tried: Verney, at p. 376; R. v. Sadikov, 2014 ONCA 72, 305 C.C.C. (3d) 421, at para. 49.
 Second, and as a consequence of the fairness origins of the rule, a trial judge is best suited to take the temperature of a trial proceeding and to assess whether any unfairness has been visited on a party because of the failure to cross-examine. Consequently, the trial judge’s decision about whether the rule has been offended and unfairness has resulted is entitled to considerable deference on appeal: Giroux, at para. 49.