Evidence - From Lawyer's File. Caledon (Town) v. Darzi Holdings Ltd.
In Caledon (Town) v. Darzi Holdings Ltd. (Ont CA, 2022) the Court of Appeal considered the interaction between breach of the Rules of Professional Conduct and the evidentiary admissibility of solicitor file materials:
 The decision of this court in Cowles v. Balac (2006), 2006 CanLII 34916 (ON CA), 83 O.R. (3d) 660 (C.A.), remains the controlling authority on the issue. In his dissent, Borins J.A. stated, at para. 198:
The Law Society passed the Rules of Professional Conduct to ensure that its members maintain the highest standards of professional conduct. Where a member's contravention of a rule is brought to the attention of the Law Society, it may result in the commencement of a disciplinary proceeding against the member. However, the Rules of Professional Conduct do not, and could not, affect the admissibility of relevant evidence in civil or criminal proceedings. Thus, even if it could be said that counsel for ALS contravened rule 4.03(2), this would not affect the admissibility of relevant evidence acquired by the investigator. [Emphasis added] The majority of the panel agreed, at para. 94, with Borins J.A. on this point.
 Although a breach of the Rules of Professional Conduct cannot determine the admissibility of evidence in a civil proceeding, a court may take such a breach into account as part of the exercise of its inherent jurisdiction to control its own process: see, e.g., Gagnon v. Pritchard (2002), 2002 CanLII 49419 (ON SC), 58 O.R. (3d) 557 (S.C.), at paras. 55-56; Dumais v. Zarnett (1996), 1996 CanLII 8205 (ON SC), 30 O.R. (3d) 431 (S.C.), at para. 49, in which courts refused to allow the use of transcripts of examinations for discovery conducted by unlicensed persons in breach of the Rules.