The fortunes of the port town of Barrow-in-Furness have long been tied to the British defense industry. Generations of its families have spent their entire working life at ¡°the yard,¡± where the U.K.¡¯s nuclear submarines are built.

Today, two-thirds of the town¡¯s working population is employed by BAE Systems PLC, which operates the shipyard, its vast Devonshire Dock Hall dominating the local skyline.

When it comes to elections, ¡°Barrow is one of the the very few seats in the country that can be decisively swayed by a single national issue,¡± said John Woodcock, who was Labour MP for Barrow-in-Furness until 2015. ¡°It¡¯s always jobs in the shipyard.¡±