The point i was making was that it's too glib to talk about Rule Britannia as a British anthem.
The concept of the UK is a relatively new one, as we know it today, it's only 80 odd years. As I pointed out, when RB was written, Ireland wasn't yet a part of the UK and although Scotland had joined with Britain as United Kingdom, it was still an alien concept to many Britons (the second Jacobite uprising was only five years away). I believe also that the Royal Navy was still known as the English navy at the time.
The Romans used Britannia to describe England and Wales (just to show I didn't fall asleep in Latin lessons). Later on, the terms Anglia and Cambria were used in their place.
Of course it's more complex than that: words and phrases are interchangeable and boundaries shift but all talk of Rule Britannia as a British song is wide of the mark. The intent was clearly a celebration of Englishness (and I know that Alfred wasn't a king of all-England), in particular, Alfred's role in setting up a permanent navy.
It's interesting to compare RB with the National Anthem. GSTQ has now been adopted as the anthem of the UK, yet as one of the later verses talks of scattering the rebellious Scots, its clear that this is also an English song that has been extended beyond the English borders.
And one final irony: the author of the words of Rule Britannia, James Thompson, was born in Scotland, but worked in London.