Nationalism is a hard thing to pin on the British really-yes, we enjoy the odd bit of flag waving at appropriate occasions, but the British and their residual assumption that overt displays of emotion are `not the done thing` (much reduced these days, but the British do still retain a remnant of the stiff upper lip) would frown on the over emotional American style flag waving-i think it was no less than the PM David Cameron who said `we dont do flags on the lawn`-could you imagine a US president saying that?
Even the individual nations of the UK are only really focus of identity when it comes to sporting events and the odd event where we end up comparing ourselves against other nations of the UK-other than that, we are gleefully self critical
It would be too difficult really.