Lawyers may be sued by someone other than client for trial conduct:

Amato v. Welsh, 2013 ONCA 258 is a pleadings case. Accordingly it needs only to find a proposition of law is tenable. That said, it is a very important decision holding a lawyer may be sued by someone other than the lawyer's client for things said or done during trial. Whether this will open the floodgates to litigation, especially in a family law context, will be seen. Disappointed family law litigants often complain the other lawyer was wrongfully in cahoots with their client - many doubtful law society complaints are seen in this context:

[83]       Notably, in Demarco, Krever J. did address the issue whether the doctrine of absolute privilege operates as a shield against negligence claims by clients against their lawyers.  His comments in rejecting this proposition, at para. 29, bear repetition:

The last consideration to be dealt with is the perceived anomaly related to the absolute privilege enjoyed in respect of anything said in Court by a lawyer.  I confess that I am unable to appreciate why it should follow from the existence of that privilege that a lawyer may not be sued by his or her client for the negligent performance of the conduct of the client's case in Court.

[84]       If, as Demarco holds, absolute privilege does not immunize Ontario lawyers from professional negligence suits by their clients, can it be said that the privilege indisputably applies when the suit is brought by Client A in respect of conduct by the lawyer on behalf of Client B?  In such circumstances, a conflict arises between the public policy goals served by the doctrine of absolute privilege and those fostered by the lawyer's duty of loyalty.  And that conflict leads to my fourth ground for rejecting the appellants' attack on the Challenged Paragraphs of the respondents' pleading.