LONDON — It was one more reminder, delivered before dawn on Christmas morning, that Britain is not only an island nation, but one that finds itself increasingly alone.
A decision by the United States to require all airline passengers arriving from Britain to test negative for the coronavirus within 72 hours of their departure, starting on Monday, was not so much a shock as it was another bitter pill in a somber holiday season.
There is the fast spread of a coronavirus variant feared to be more contagious. Dozens of nations have barred travelers from Britain from entering. Expanded lockdowns
