British Prime Minister Theresa May is launching a new working group to look for a plan B on Brexit, but the leader's latest initiative comes too late to stop businesses such as Nissan Motor Co. from ditching key commitments to the U.K.

The automaker cited ongoing doubts about the U.K.'s split from the European Union in its decision to scrap plans to make the X-Trail sport utility vehicle at the Sunderland plant, its biggest auto factory in the country. May's government had previously gone out on a limb to safeguard Nissan's investment in the U.K., offering assurances in a private letter.

"We appreciate this will be disappointing for our U.K. team and partners," Nissan Europe Chairman Gianluca de Ficchy said in a statement Sunday. "The continued uncertainty around the U.K.'s future relationship with the EU is not helping companies like ours to plan for the future."