The origins of the British National Anthem are well described by Percy Scholes in his little book "God Save the Queen!". (He could have gone further to look at later uses and pisstakes of it, though). It doesn't make any sense to think of it as English - it was specifically intended as the *King's* anthem when it was written, and the King was George II, King of Britain.

It's a terrific tune. I think only Montenegro and Abkhazia have better ones. (Abkhazia's anthem also has awe-inspiring words).