Contract talks between automaker Stellantis NV STLA-N and Unifor have broken off after hitting an impasse over the future of the idled Brampton, Ont., assembly plant, the union says.

Stellantis confirmed to the union it has signed a memorandum of understanding with defence industry supplier Roshel, which wants to buy the factory near Toronto, Unifor said in a statement on Friday.

“The persistence of the company’s proposal to close and sell the Brampton plant has hindered the bargaining process,” Unifor said.

The two sides began bargaining on Sept. 1, with the union seeking a three-year deal by Sept. 11 that matched the gains made in recent negotiations with Ford and General Motors. Those agreements provided raises of 3 per cent in each year of the deals.

In the Stellantis talks, Unifor had said its priorities were securing a future for the Brampton assembly plant west of Toronto that was idled in 2023, as well as securing production volumes at factories in Windsor and Toronto.