To say the sun never sets implies it is worldwide. Historically England had colonies around the world. Therefore it could be said “the sun never set on the British flag.

Wikipedia (September 24, 2017) states it this way:

          The sentiment expressed by these words first appeared in Christopher                                     North’s1829 work Noctes Ambrosianae. The actual words used by Christopher North were ‘His Majesty’s dominions, on which the sun never sets’ (as these words were written in 1829, the “Majesty” in question would have been King George IV).Sep 11, 2009

Geographically there are places in the world where the sun never sets. Norway, Sweden, Finland, Alaska, Iceland and Greenland experience 24 hours of sunlight for about half the year. For those not accustomed to daylight during the midnight hours it is a worthwhile experience. Rather than rise in the east and set in the west, the sun continues to move across the horizon. Definitely, it is the view that validates how the earth rotates around the sun. Or is it that the sun rotates around the earth?