Things fall apart; the centre does not hold. Last summer most of us in the McChattering classes thought that, once "capability" Gordon Brown entered Number 10, many Scots would start to lose their infatuation with nationalism and revert to their traditional allegiance to Labour. Hasn't happened. Indeed, the moral and political disintegration of Gordon Brown's leadership, which this column examined last week, may now be one of the factors that hastens the disintegration of the UK.

It's just that no-one ever thought it could possibly be as bad as this. Fights breaking out in cabinet; ministers jostling for the succession; a paralysed Prime Minister unable to make decisions; an unprecedented collapse in the UK government's poll ratings. And all this at the very moment when nationalists have entered government in all three devolved legislatures. There are times when history seems to be pursuing a logic of its own. In many ways, nationalism is an anachronism in this global financial village, and yet the Scots appear to be turning to it as they never did in the days when Scotland had its own autonomous industrial economy. Recent polls, such as the TNS System Three in yesterday's Sunday Herald have shown a steady increase in support for independence over the past year.

Of course, the performance of the minority SNP administration in Holyrood has had a lot to do with this. Yet, when you think of it, the remarkable thing is that the nationalists are still in government at all, one year on, with only 47 MSPs out of 129. Alex Salmond would never have got the keys to Bute House had the unionist parties got their act together last May. Once over the threshold, there was no stopping him. The Scottish voters have been given a masterclass in radical nationalist populism - cutting prescription charges, saving accident and emergency units, abolishing student loans, axing bridge tolls etc.

The real surprise is that Gordon Brown, for all his intimate knowledge of Scottish politics, has had no answer to this, apart from a risible campaign to promote Britishness. Perhaps we should have forecast that his protege, Wendy Alexander, would be further disaster for Labour in Scotland - though I certainly didn't. She seemed to represent the way forward for Scottish Labour: female, intelligent and open-minded about constitutional reform. But she has mounted campaigns against cuts in services even as her mentor, Gordon Brown, cuts the funding to pay for them.

To complete the picture, Gordon has installed in the Scottish Office a clutch of ministers who seem determined to pursue a petty-minded and punitive campaign against Scots for the crime of voting SNP. The threats to cut off council tax benefits and to overrule the Scottish Parliament's power to introduce a local income tax were as offensive as they were politically inept. This allows the nationalists to paint Labour as neo-colonial overlords and defenders of the unpopular council tax - and may also give Salmond an excuse for not introducing his own dubious alternative while blaming Westminster.

The whisky tax in the budget was so unpopular that even Wendy Alexander's husband, the economist Professor Brian Ashcroft, condemned it. Labour's Scottish ministerial team declared their intention to take powers back from the Scottish Parliament, even as Alexander was promising to extend them. Westminster has blocked a ban on air weapons and attacked the Scottish Government for rejecting nuclear power and opposing Trident. Then there was al-Megrahi, the oath of allegiance to the Queen, the £40m elections botch up . . . it just goes on and on.

Brown must see how damaging this all is, yet he has done nothing to mitigate the emerging disaster. Perhaps his attention is elsewhere. The abolition of the 10p tax band was not intended to hit Scotland, but it will because low pay is so prevalent here. It also offends against the moral sentiments of Scots who don't see why non-doms and hedge-fund managers deserve to pay less tax than the working poor.

With political incompetence on this scale, it's not surprising that Alex Salmond has had a good year. However, it has long been the conventional wisdom - in this column as elsewhere - that despite the high approval ratings for the SNP minority Government, the Scots were essentially constitutional opportunists who might flirt with nationalism, but would always, in the end, vote to remain in the UK. But even this is now brought into question.

Yesterday's TNS System Three poll, indicating a slim majority in favour of negotiated independence on the SNP's terms - 41% for to 40% against - cannot be ignored. Only last August, TNS was registering a 15% lead for staying in the Union. A Scottish Opinion poll last week also showed independence running neck-and-neck with the Union - 41% for; 43% against. It's too early to say that Scots are now committed to leaving the UK, but something is certainly stirring in the undergrowth of Scottish public opinion. We may now have to start thinking about independence as a realistic option for Scotland.

Yet again, this seems counterintuitive because the present financial climate doesn't look at all propitious for the cause of independence. It's a cruel world out there - look at what's happening in Iceland, where a small independent country has had to increase interest rates to 15% to fight off international financial predators. The Irish tiger is looking pretty sick, too. In the past, at times of national emergency, the Union has generally been strengthened by a collective sense that we are "in this together".

That may still hold true. The impact of the financial turbulence has yet fully to hit home in Scotland, and when it does Scots might again seek security in the Union. Then again, they might not. After having had a taste of autonomy over the past year, I don't see much enthusiasm for returning to the old dependency culture. There are now so many examples of highly successful small countries in and out of the EU, from Norway to Slovakia, that going it alone no longer means being alone.

Moreover, the rise of the London city state and the fall of the welfare state consensus that united these islands in the half-century after the war, has eroded the ties that used to bind the UK together.

London is now a leading hub of the international plutocracy and barely conscious of the existence of the UK hinterland, whether in England or Scotland. As the economy slides into recession, Scots will be watching very closely to see who wins and who loses. But, right now, the biggest loser is Gordon Brown.