Testimony of a professional

R. v. Ashmore, 2011 BCCA 18 is helpful in setting out the principle that the regular practice of a professional may be convincing evidence of what that professional did on a specific occasion:




[61]           It was open to the trial judge to prefer Mr. Dumonceaux's evidence for the reasons he gave.  In this regard, it is to be remembered that testimony regarding standard or habitual practice, even standing alone, can serve as the basis for finding that something was done in a certain way.  As Mr. Justice Seaton stated in Belknap v. Meakes ⁠reflex, (1989), 64 D.L.R. (4th) 452 at 465 (B.C.C.A.):

            If a person can say of something he regularly does in his professional life that he invariably does it in a certain way, that surely is evidence and possibly convincing evidence, that he did it in that way on the day in question.

See also:  R. v. Thompson 2001 CanLII 24186 (ON C.A.), (2001), 151 C.C.C. (3d) 339 at paras. 7-9 (Ont. C.A.); R. v. Cunningham, 2006 ABCA 345 (CanLII), 2006 ABCA 345, 401 A.R. 35 at paras. 4, 5.