Lisa Roley has worked at Nissan Motor Co.'s car plant in Sunderland, U.K., for the past two decades. Like the majority of people in the city, she also voted to leave the European Union in 2016.

A day after the Japanese manufacturing giant pointed a finger at Brexit as it abandoned plans to build a new model at the factory in northeast England, the 47-year-old cleaner was questioning her decision. The warnings from some local politicians and executives of what might happen were no longer being dismissed as fantasy.

"I'm not so sure now," said Roley, as she waited for the bus back to her home four miles away from the sprawling grey Nissan complex. "They're saying on the telly it's going to affect a lot of businesses."