Par Expert: la confidentialité afférente aux communications avocat-client s'applique également aux communications entre l'avocat et un expert potentiel

par Karim Renno
Irving Mitchell Kalichman s.e.n.c.r.l.

Nous en discutions dans le cadre de notre rubrique Par Expert la semaine dernière à propos de l'affaire Poulin c. Prat (1994 CanLII 5421): la règle générale en droit québécois veut que l'on ne peut obtenir la communication des ébauches d'expertise préparées par un témoin expert à moins qu'il n'y réfère dans son rapport définitif. Or, comme le soulignait la Cour supérieure dans Widdrington c. Wightman (2003 CanLII 33199), cette règle s'applique également aux autres communications écrites entre l'expert et l'avocat qui l'a mandaté.

Dans cette affaire, l'Honorable juge Paul P. Carrière doit trancher une objection soulevée pendant le procès à la communication d'une lettre écrite par le témoin expert qui est contre-interrogé à l'avocat qui lui a donné mandat. Dans cette lettre, l'expert émettait une opinion préliminaire.

Le juge Carrière accueille cette objection, étant d'avis que cette lettre est protégée par la confidentialité des communications entre un expert et l'avocat qui l'a mandaté:

Given the particular circumstances leading up to question No. 70, the court has difficulty in accepting that a lawyer may, during cross-examination, ask a witness to consult a letter just to confirm its date and subsequently request its production on the basis that he consulted it while in the witness box. This is tantamount to accepting that just about any means of obtaining evidence is a proper basis for overcoming the confidentiality of the lawyer/client privilege extended to communications between the client's expert and lawyer. 

In the matter of R. v. Perron, Mr. Justice Michel Proulx of the Quebec Court of Appeal, after stressing that the waiver of so fundamental a right as that pertaining to the confidentiality of a report must be clear, cited the following extract from McCormick "On Evidence": 

Since, as we have seen, it is the client who is the holder of the privilege, the power to waive it is his, and he alone, or his attorney or agent acting with his authority, or his representative may exercise this power. Waiver includes, as Wigmore points out, not merely words or conduct expressing an intention to relinquish a known right, but conduct, such as a partial disclosure, which would make it unfair for the client to insist on the privilege thereafter.  

The holder of the privilege, Richter & Associés Inc, was represented at trial on January 10th, 2003 solely by its counsel, Me Leonard Flanz; in the court's opinion, it cannot be reasonably argued that the latter's words or conduct expressed an intention to relinquish the confidentiality attached to this letter. 

The court finds no valid reason to conclude that the notion of fairness demands that Defendants be entitled to the disclosure of Mr. Vance's letter to co-counsel acting for Richter & Associés Inc since the communication contained therein was not disclosed during cross-examination; that said, it also follows that the rule of public interest in the disclosure of all relevant evidence before the court doesn't outweigh the need in the present case to maintain the confidentiality attached to this letter.

Référence : [2014] ABD Expert 10

Autre décision citée dans le présent billet:

1. R. c. Perron, , 1990 CanLII 3396 (C.A.).