TORONTO - A potentially precedent-setting Internet privacy case involving a one-time beer commercial actor charged with child porn offences is set to hear arguments tomorrow.

Robert Norman Smith played an angry Scotsman in ads for Alexander Keith's beer until he was charged in 2006 with two counts of possession of child pornography and one of making it available over the Internet.

As his trial was set to begin this week, his lawyer launched a constitutional challenge of the search warrant that led to his arrest.

Cindy Wasser said her client's privacy was violated when Internet provider Bell Canada gave his name and address to Toronto police.

The action is believed to be the first Ontario Superior Court challenge of its kind.

Lawyers spent today arguing whether a key defence witness could be considered an expert in computer forensics and peer-to-peer networks.

Justice Robert Clark is expected to decide tomorrow whether to accept Russ Doucet's evidence, then hear submissions on the search warrant.

Police allege Smith's computer contained more than 200 images of graphic sex involving children as young as a year old.