“A lawyer owes no duty of care to clients of opposing counsel in court proceedings. Lawyers owe a duty of care to their own clients. Suing opposing counsel because of the manner in which they litigate is generally an abuse of process: Ahsan v. Minden Gross LLP, 2024 ONSC 1307 at paras 5 and 6. If a lawyer owed a duty to both their own client and to the opposing party, the lawyer would be in a conflict of interest: Robins v. 2758729 Ontario Inc. et al, 2023 ONSC 4367, at para. 25.
To allow a claim against an opposing party’s counsel would be against public policy. Such a claim would interfere with the loyalty between a solicitor and their client and encourage re-litigation and collateral attacks on decisions reached in the disputes between litigants. It would fundamentally alter the adversarial legal system for a lawyer for one party in a legal proceeding to be accountable to the other party to conduct the proceeding in good faith: Crown Crest Financial Corp. v. Sabbah, 2019 ONSC 7114, 61 C.C.L.T. (4th) 292, at paras. 26-28; Chuvalo v. Worsoff, 2022 ONSC 4079, 75 R.F.L. (8th) 94.
In Chuvalo, at paras. 32-33, Chown J. noted the following:
In our system, the lawyer gives advice, and the client makes decisions and instructs the lawyer. A lawyer’s advice as to strategy is typically subject to privilege and cannot be disclosed by the lawyer without the client’s consent. An adverse party who feels wronged by the strategy taken is not entitled to know if the strategy was taken in accordance with or against the adverse lawyer’s advice. Parties cannot get around this by suing the adverse lawyer.
Our system requires that any complaint over the strategy taken by an adverse party must be resolved in the litigation where that strategy was taken, and not in a further lawsuit. If our system was without this feature, serial lawsuits could spawn from a single underlying dispute. “There would be a temptation, which many would find irresistible, to relitigate in actions against their opponent’s counsel the issues which they have lost in the main litigation, or to attempt to handicap the other side by eliminating experienced and knowledgeable counsel from the case.” [Footnotes omitted.]”
Spasiw v. Law Society of Ontario, 2024 ONSC 1486 (CanLII) at 47-49