I'm not sure I know enough about Scotland / Wales / England / Ireland to fairly comment here. The key difference as I understand it at least, is that India and Pakistan did not exist as nations - ever - they were both nations created "artificially" out of the greater Indian sub-continent. India walked away with the history of the ancient indian civilization and everything from then on as its own story - Pakistan emerged as "we're not India, we're a muslim nation". I see where you're coming from - but the problems here run significantly deeper than sports rivalries!
Scotland is currently preparing for a referendum on splitting from the UK (which really means, as far as Scots are concerned, splitting from England).
In what I'm sure is a complete coincidence, the referendum is going to be in the same year as the 700th anniversary of the climactic battle of the Scottish War of Independence at Bannockburn.
The divisions between Scots and English really do go quite deep - at least from the Scottish side, not sure that the average Englishmen cares and if they do it's probably to wish us good riddance.... :-)
Are you aware of "The Troubles", the 25-ish year campaign of insurrection carried out by Northern Irish separatists? I would suggest that's closer to "open warfare" than it is supporting a football team.
