I also do not like the 'Britain' thing. Sure, I know that what's written in the Japanese manga but strips very clearly suggest that it's about England. I mean - it was England who defeated the Armada, got conquered by the Normans and such.

But it wasn't only England who participated in the world wars, the Austrian War of Succession, or even the American Revolution... I think Himaruya just called him "Igirisu" back in the times when he was only England or Great Britain for simplicity's sake. Himaruya himself confirmed in one of the now-deleted blog entries that he's Britain except when he's dealing with his siblings - then he's England. It's just fandom that started to call him England, and it became so widespread that people react badly to the change.