The Canadian Auto Workers union lifted its blockade of the General Motors of Canada headquarters in Oshawa, Ontario, today after it was ordered to do so by a judge.

Judge David Salmers of the Superior Court of Justice in the Canadian province of Ontario on Friday ordered the union to end its blockade from 7am Canadian time Monday (noon BST) but blasted General Motors for the way it handled the announcement of the closing of its Oshawa truck plant.

That closing was announced two weeks after the company and the CAW reached a deal on a new contract that called for the plant to assemble the next generation of GM's full-sized pickups in 2011 and for the company to give the union advance notice and time to discuss alternatives if there were any changes in that plan.

The decision to close a large plant would not be made lightly or quickly and executives at GM would have been aware of the need to shut the facility before 1 June, when the car maker told the union, Judge Salmers wrote.

His nine-page ruling was released late Friday after a full-day hearing on an injunction sought by GM to end the blockade.

"I find that GM Corporation engaged in almost deceitful business practice by allowing GM Canada's lead negotiators to agree to the advance notice and discussion clauses in the 15 May, 2008 agreement at a time when the truck business was in dire straits and when GM should have been at least aware of the possibility that plants, possibly including the Oshawa truck plant, might have to be closed," the judge wrote.

Union officials will meet this week to plot further strategy, said Chris Buckley, president of CAW local 222, which represents workers at GM's massive operations in Oshawa, east of Toronto.

The union still hopes to convince GM to reverse the decision to close the plant, which will wipe out 2,600 direct jobs and thousands more at suppliers in the area. It is scheduled to close in 2011.