In the United States, the Stars and Stripes are everywhere: on porches, lawns and pickup trucks. The national flag is part of the scenery, almost invisible in its ubiquity. In England, flags are rarer ...

RUGBY, England—Stuart Field raised his first flags in July: the English red cross of St. George and also a smattering of the British red, white and blue, hanging them from his hometown’s streetlights.

Social media and British media have been consumed and divided in recent weeks by the growing number of people raising the St. George’s and Union Jack flags, so why the controversy? Dubbed ‘Operation ...