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John Mather

DMG Advocates LLP

John Mather is a partner at DMG Advocates LLP, a law firm based in Toronto. John practices commercial and public litigation. John regularly acts in defamation proceedings and access-to-information proceedings. He has acted as an advisor to journalists, media organizations and individuals.

John’s public litigation practice has focused on public inquiries. From 2019-2020, John served as Inquiry Counsel to Justice Frank Marrocco at the Collingwood Inquiry. In 2022 and 2023, he acted as Commission Counsel to Justice Paul Rouleau at the Public Order Emergency Commission, which examined the federal government’s decision to invoke the Emergencies Act in response to the convoy protests in Ottawa, Windsor and other locations. 

Through public inquiries, John has significant experience in dealing with public disclosure of government information, and the challenges presented by claims of cabinet confidence and national security confidentiality. John represented the Centre for Free Expression at the Foreign Interference Inquiry.