Representation - Lawyers - Conflict of Interest. R. v. Marrone
In R. v. Marrone (Ont CA, 2023) the Court of Appeal considers conflict of interest respecting trial counsel:
 Where an allegation of conflict of interest is raised on appeal, the appellant is required to demonstrate two things: (i) that trial counsel was in an actual conflict of interest; and (ii) that the conflict impaired trial counsel’s representation, in the sense that counsel’s representation was, in fact, adversely affected. The latter question is judged by what happened, not what might have happened. The Court will find that a miscarriage of justice occurred only if both branches of this test are met: R. v. W.W., (1995) 1995 CanLII 3505 (ON CA), 25 O.R. (3d) 161 (C.A.), at p. 173; R. v. Faudar, 2021 ONCA 226, 403 C.C.C. (3d) 43, at paras. 59-61.. R. v. Faudar
In R. v. Faudar (Ont CA, 2021) the Court of Appeal considered a lawyer's duty to avoid conflict of interest:
 A lawyer owes a duty to their client to avoid conflicts of interest: Baharloo, at para. 31. Section 1.1-1 of the Law Society of Ontario’s Rules of Professional Conduct defines a “conflict of interest” as a substantial risk that a lawyer’s loyalty to, or representation of, a client would be materially and adversely affected by the lawyer’s duties to a former client.. Lepan v. Lofranco
 The rule against conflicts guards against two forms of prejudice: first, there is “prejudice as a result of the lawyer's misuse of confidential information obtained from a client”; and second, there is “prejudice arising where the lawyer ‘soft peddles’ his representation of a client in order to serve his own interests, those of another client, or those of a third person”: Canadian National Railway Co. v. McKercher LLP, 2013 SCC 39,  2 S.C.R. 649, at para. 23.
 With respect to former clients, lawyers must refrain from misusing confidential information. Whereas, for current clients, lawyers must not misuse confidential information, nor place themselves in a situation that jeopardizes effective representation: Canadian National Railway Co., at para. 23.
 A lawyer can render effective assistance only when that lawyer champions the accused’s cause with undivided loyalty: W. (W.), at p. 13. Effective representation may be threatened where a lawyer is tempted to prefer other interests over those of their client: Canadian National Railway Co., at para. 26. As this court wrote in R. v. McCallen (1999), 1999 CanLII 3685 (ON CA), 43 O.R. (3d) 56 (C.A.), at p. 67, cited with approval by the Supreme Court in R. v. Neil, 2002 SCC 70,  3 S.C.R. 631, at para. 12: “There should be no room for doubt about counsel's loyalty and dedication to the client's case.” A lawyer’s duty of loyalty to their client is foundational to the adversarial system and “essential to the integrity of the administration of justice”: Neil, at para. 12.
 This court has identified specific criteria to determine where a conflict of interest causes a denial of the accused’s constitutional right to make a full answer and defence, and results in a miscarriage of justice. As Doherty J.A. wrote in W. (W.), at pp. 15-16, the appellant must show:
i. an actual conflict of interest between the respective interests represented by counsel; and If both criteria are established, then the appellant has been denied the right to make full answer and defence and a miscarriage of justice has occurred: W. (W.), at p. 16.
ii. as a result of that conflict, some impairment of counsel’s ability to represent effectively the interests of the appellant.
 It is not enough simply to have an appearance of a conflict. The court must determine whether counsel’s representation was, in fact, adversely affected. The concern on appeal must be with what happened and not what might have happened: W. (W.), at pp. 17-19.
 The cases provided by the parties on this issue, namely Baharloo and W. (W.), consider the issue of a potential conflict of interest with another “current client”, as opposed to a former client. However, if the trial counsel’s representation of an accused may be compromised by a duty to a former client, counsel should first advise the new client and obtain their consent. If counsel believes that the duty to the former client actually will compromise the new retainer, then the lawyer should decline to accept the case.
In Lepan v. Lofranco (Div Ct, 2021) the Divisional Court considered the conflict of interest test for counsel:
 The Court has the inherent jurisdiction to remove from the record solicitors who have a conflict of interest: see MacDonald Estate v. Martin, 1990 CanLII 32 (SCC),  3 S.C.R. 1235, at 1245.
 At page 1243 of MacDonald, the Supreme Court set out the general principles to be considered on a motion to disqualify for conflict of interest. A court will seek to balance three competing public policy values:
a) the maintenance of high standards of the legal profession and the integrity of our system of justice;
b) the right of a litigant to its choice of counsel, which he or she should not be deprived of without good cause; and
c) the desirability to permit mobility in the legal profession.