Well, the sun hasn't set on British holdings for over 200 years because when the sun sets for the western oversea territories it rises over the eastern ones, so you can rule the waves, we'll keep the pride of the sun nog setting on us yet. A much grander claim to fame I think.

And international maritime law is based off British maritime law, so de jure we do "rule" the waves!

Admittedly if would help if Westministers ilk didn't keep going "hurt durr, we no need navy, budget cut!" every few months. Hard to rule the waves with a handful of fishing trawlers...