After the provincial labour relations board heard contentious arguments from both sides for more than 16 hours on Saturday, the hearing to establish the legality of a strike by 55,000 Ontario education workers continued Sunday morning.

The board was informed by a lawyer representing the Canadian Union of Public Employees that granting the government’s request to deem the strike illegal would imply that labour rules and the right to collective bargaining are no longer in effect.

In order to protect itself from constitutional challenges, the Progressive Conservative administration incorporated the notwithstanding clause into the education worker legislation that forbade strikes and imposed a four-year contract on union members.

On Friday, thousands of workers, including librarians, custodians, and education assistants, left their jobs in protest. According to CUPE, the strike may last indefinitely.

Citing case law, Steven Barrett, a lawyer for CUPE, contended Ontario utilised the clause in an unusual and improper way to handle labour difficulties.

The government’s attorney, Ferina Murji, replied that if the labour board does not deem the walkout illegal, it runs the risk of undermining the province’s own labour rules.