On a wet Wednesday morning in April, Ashley Holroyd had a steady but slow stream of customers into his coffee shop in Barrow-in-Furness, an industrial town in northwest England. The cafe, Coffee D’Ash, had been open for only about six months, and it barely filled the cavernous space.

Despite the empty storefronts on the same street, Mr. Holroyd is certain he has a prime location. BAE Systems, Britain’s largest defense company, is planning to open a training facility for hundreds of workers right next door.

Mr. Holroyd, 33, jumped at the chance to expand his coffee business from a trailer into a brick-and-mortar store after he heard about BAE’s plans to move into the town center — crucially, without a cafeteria for the employees.

“If I don’t, someone else will,” he said. “It was a bigger risk not to do it.”

BAE is the major employer in Barrow, where it makes nuclear submarines for the Royal Navy in a shipyard at the edge of town. Like many other defense companies, BAE is in the midst of a rapid expansion because of an increase in military spending in Britain.

Governments throughout Europe are pledging to spend more on defense. They are re-evaluating their military capabilities and reliance on American defense after they became concerned about President Trump’s commitment to supporting Ukraine in its war against Russia.

The British government is increasing military spending to 2.5 percent of the country’s gross domestic product by 2027, and to 3 percent by the end of the decade. This year, the Treasury will spend an extra 2.2 billion pounds ($2.9 billion). But officials want to ensure that the money feeds through to create domestic jobs and generate local prosperity.