It's part of what's mandatory for us...at least in California. People can keep you out if you are not wearing a mask.
So I don't know what the rate of infection is in the U.K. but they are not availing themselves of whatever protection a mask might provide and that seems very shortsighted to me...as an outside observer.
Different strokes.
What effect a mask actually provides is unknown to me. But I'd rather be with it than without it.