A Montreal employees union could be forced to pay millions of dollars in compensation to drivers caught in a 2003 protest, if a class-action lawsuit underway in Quebec superior court is successful.

About 35,000 drivers joined the lawsuit after they were caught in a massive traffic jam that mushroomed during a blue-collar worker protest on Sept. 17 2003, when city employees used municipal trucks to block off several main streets in downtown Montreal, paralyzing traffic for several hours. 

The class-action will try to prove the protest was illegal, and victimized drivers who have a right to compensation, said Bruce Johnston, a lawyer representing the motorists.

"Our thesis is that this was an intentional and illegal move, and that tens of thousands of people who were caught in traffic that morning have a right to compensation for that," he told Radio-Canada.

During the first day of hearings Monday, Montreal police Commander Denis Desroches testified the union did not seek an official permit to stage a protest. He also told the court the protest gripped the downtown core for several hours, turning it into a parking lot for blocks on end.

The union, affiliated with the Fédération des travailleurs et travailleuses du Québec (FTQ), denies doing anything wrong, said Michel Derouet, a lawyer representing the workers. "There was a protest. We will submit our arguments to the judge," he told Radio-Canada

The employees were protesting contract negotiations with the city.

The class-action is seeking $650 in damages for every driver caught in the jam for a total of $23 million. Lawsuit hearings will continue until the end of March.