http://scc-csc.lexum.com/scc-csc/scc-csc/en/item/15328/index.do 
White Burgess Langille Inman v. Abbott and Hamilton Co. (April 30, 2015 – 2015 SCC 23, Cromwell J. (McLachlin C.J. and Abella, Rothstein, Moldaver, Wagner and Gascon JJ. concurring)).
Précis: In this decision the Supreme Court of Canada upheld a decision of a majority of the Nova Scotia Court of Appeal which reversed the decision of a motions Judge to exclude an expert report of a Grant Thornton accountant dealing with alleged negligence on the part of the defendant accounting firm, White Burgess Langille Inman. The allegation was that the expert was not impartial since another office of Grant Thornton had done accounting work for the plaintiff which might cause her to tailor her evidence. The Supreme Court ruled that an expert report should only be excluded for want of impartiality in the clearest of cases. A trial judge should apply the four branches of the
Mohan test and then “determine, having regard to both the particular circumstances of the proposed expert and the substance of the proposed evidence, whether the expert is able and willing to carry out his or her primary duty to the court” [para. [49]].
Decision: While this is not a tax case, it is bound to be one of considerable importance in tax cases in future. Expert evidence is seen increasingly in tax litigation including such matters as treaty interpretation, valuation, transfer pricing, etc. This decision was a major victory for Jon Laxer and Brian F. P. Murphy, for the respondents. [Lenczner Slaght Royce Smith Griffin, Toronto; Groupe Murphy Group, Moncton.] Additional discussion of the Supreme Court’s decision can be found in a related post on the Lenczner Slaght blog:
http://www.litigate.com/the-admission-of-expert-evidence-the-role-of-impartiality