Whatever happens today, the future gets interesting. If the Scots vote to leave the UK then I don't care how much David Cameron says he won't resign, I don't think parliament will give him a choice. Votes of no confidence have been called over lesser mistakes than losing a quarter of the nation.
Now, whatever you've been told the electoral maths of the next general election won't change that much. Yes, Labour will lose a lot of safe seats but, at the end of the day, one of problems the Scots are having is that their voting power in parliament is too small to get anything done for themselves. Scotland is large but not that densely populated. Greater London and the South decide every election and losing Scotland is not going to change that all that much.
What it will mean is that politicians will have received a massive wake up call. The call for referendum has been building for years but it came under this government and if independence goes through it will be indelibly linked to them: a coalition government that could not achieve an electoral majority when the Tories were at their most popular in decades and which has systemically reneged on every manifesto promise it made before the election.
Scottish Independence could be the knock in the head our political class needs.
Then there's the eventuality that Scotland stay in the union. Not my preferred outcome but I'd be willing to bet it'll be close either way.
Nevertheless, even if Scotland stays the precedent is set. The beauty of having an unwritten constitution is everything is, in theory, legal until proven otherwise. Now, there has been at least one similar referendum like this in the past with Northern Ireland but Northern Ireland is a whole mess of issues too extensive to list here and has a rather different relationship with the greater union. Ireland has always been, in the view of its independence movement at least, a colonial holding whilst Scotland is the country that merged with England to create the United Kingdom.
If a founding member of the union can call for independence then literally any part of the UK with a strong historical or cultural claim to autonomy can do so. I mean, Northern Ireland will be first, don't get me wrong, but I expect to see Wales and Cornwall getting on the bandwagon. Maybe even the North if a large enough body of counties can club together to create enough leverage on Westminster.
Seriously interesting times ahead.