ONCA to Consider Application of Deemed Undertaking Rule to Producing-Party's Own Lawyer

In Sobeski v. Mamo, now on appeal to the Ontario Court of Appeal, Justice Perell heard a motion by a defendant in a defamation action for relief from the deemed undertaking rule.


The defendant in the defamation action was a lawyer who, in a previous piece of litigation, had represented the opposing party to the plaintiff in the defamation action. In the defamation action, the plaintiff alleged that the defendant-lawyer had made defamatory remarks about him to the media during the previous litigation. The defendant-lawyer had told the media that the plaintiff's version of events in the previous litigation was "a purgered account".

The defendant-lawyer sought to rely on documents and evidence produced by his former client in the previous litigation to establish the defences of truth and qualified privilege in the defamation action. He moved for relief from the deemed undertaking rule for this purpose.


The Court refused to grant relief from the deemed undertaking rule. The Court emphasized that the defendant-lawyer's former client (who had produced the evidence to which the deemed undertaking applied) had not consented to the motion. That former client had been compelled to produce that evidence in the previous proceeding and had the right to have that evidence kept confidential.

According to the Court, the defendant-lawyer had also failed to establish that the defences he wished to advance in the defamation action could not be made out without the subject documents.

The Court provided directions to the defendant-lawyer to return the subject evidence to his former client and to then list those documents as being formerly in his possession and control in his Affidavit of Documents. Once the documents are returned to his former client, the defendant-lawyer would be free to bring a motion for leave to obtain discovery evidence from the former client.

Finally, the Court also emphasized that both parties would be free to call the former client as a witness at trial in the defamation action to deal with any issues.

Potential Significance

This case provides the Ontario Court of Appeal with an opportunity to consider the interplay between two important interests. First, the privacy and confidentiality interests of parties to litigation, who are compelled to produce documents. This interest is protected by the deemed undertaking rule. Second, the right of defendants in civil litigation to fully defend the allegations made against them.

Case Information

Sobeski v. Mamo

Ontario Court of Appeal Court File No: C53659

Motion Hearing Date: March 8, 2012

defamation Ontario Court of Appeal relief from deemed undertaking rule



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