A STRIKE by 10,000 Air Canada flight attendants was declared illegal today, with the Canada Industrial Relations Board (CIRB) ordering them back to work after they ignored an earlier order to end the strike and submit to arbitration.

The strike at Canada’s largest airline has brought the usual peak summer travel to a standstill.

After three days of strike action, the two sides remain far apart on pay and other issues in contract negotiations. Air Canada suspended plans to restart operations on Sunday after the union defied a return-to-work order.

“The members of the union’s bargaining unit are directed to resume the performance of their duties immediately and to refrain from engaging in unlawful strike activities,” the CIRB said in a written decision.

The board, an independent administrative tribunal that interprets and applies Canada’s employment laws, said the union had to provide written notice to all of its members by noon today that they must resume their duties.

It was not immediately clear what recourse the board or the government has if the union continues to refuse.

The panel had previously ordered airline staff back to work by 2pm on Sunday after the government intervened.

Air Canada said in a statement that the union had “illegally directed its flight attendant members to defy a direction from the CIRB.”

On Sunday, Canadian Union of Public Employees national president Mark Hancock had ripped up a copy of the initial back-to-work order outside Toronto’s Pearson International Airport and vowed that members wouldn’t end the strike this week.

“Our members are not going back to work,” Mr Hancock insisted. “We are saying no.”

Picketing flight attendants chanted: “Don’t blame me, blame AC” outside the departure terminal.

Federal Jobs Minister Patty Hajdu had ordered the 10,000 flight attendants back to work, saying now was not the time to take risks with Canada’s economy.