That isn't very reassuring unless we know the strength of those.

I'd say much less than any of those. I'm from an Irish family living in Britain, and in my experience everyone thinks of the Irish as a type of British. To take a potentially frivolous example - listen to complaints about football players all being foreigners. You often hear statisics about how few teams field players made up only of British and Irish players - the Irish don't count as foreign. Yes, it's only football, but I think it represents a larger mindset. When people makes jokes about Irish stereotypes, they don't seem to think of them as outsiders - it's no different to the 'southern fairy' and 'northern monkey' stereotypes.

Southern Fairy? Never heard that one before.

I may be wrong, but I think in Britain, the south (where London is) is the posh, cultured, rich and therefore effete place, while the North is supposed to be full of rugged, rough drunken football louts.