Bruce Anderson: Gordon Brown thought he could rely on the Scottish vote – now it could bring him down

There was a New York bagel maker called Finkelstein. He was the most unfortunate of men. The day after the insurance policy ran out, his store burnt down, which did not persuade the health authorities to drop the charges over the mice in his basement: placed there, he was certain, by a rival. On Yom Kippur, his daughter and only child announced that she was going to marry a goy. Truly, his suffering exceeded Job's. He was so desperate that he shook his fist at the sky and shouted: "God, why are you so down on me?" To his astonishment, the clouds parted, and there was God, saying: "I don't know what it is, Finkelstein, but somehow you piss me off."

The God of the Kirk of Scotland is being equally unkind to Gordon Brown. From a "great clunking fist" to "what can go wrong will go wrong", and it is now going badly wrong in his own kailyard, Scotland.

For all his attempts to claim otherwise, Gordon Brown has never been at ease with Middle England. He can neither connect with the aspirations nor with the sense of humour. He regards Middle England's distrust of the state as a moral failing. But he has no doubts about his ain folk. While not going as far as Eamon de Valera – "When I want to know what the plain people of Ireland are thinking, I look into my heart" – Gordon Brown was confident of the allegiance of his clansmen. From afar, Arthur's Seat dominates the Edinburgh skyline, as it always has. Mr Brown assumed that the Scottish Labour Party, Gordon's seat, would be equally immutable.

It is now disintegrating. Alex Salmond, as successful in Scotland as David Cameron has been in England, regularly makes a monkey out of the Scots Labour hierarchy. Burnam Wood is marching on Dunsinane. But temptations to enjoy the political theatre should be resisted. Far from being a comedy, this could turn out to be a tragedy: the tragedy of the Union.

None of this was meant to happen. The senior Labour advocates of devolution all devoutly believed that it would underpin the Union, and they had a point. By 1997, it would have been almost impossible to resist the demand for devolution in Scotland. As Donald Dewar and John Smith both said, it was "the settled will of the Scottish people". Tony Blair was always uneasy about devolution. His feline political subconscious told him that there would be trouble. But at the time, he could hardly find anyone in the Labour Party to agree with him.

There were some sceptics, though not in the Labour Party. I wrote that Labour's constitutional plans were the equivalent of loosing a troop of toddlers to play in the crockery. But devo-sceps who say "I told you so" are verging on intellectual dishonesty. Back then, there was no realistic way to avert devolution.

Equally, the Labour Party is not solely to blame for the current mess. In 1997, Labour's sophisticated devolutionists were making a political calculation that they could not have avowed. They were assuming that the Scottish Tory party would revive. As the memories of Margaret Thatcher faded, the Tories would recover to at least 25 per cent of the vote. Assume that even in a catastrophe, Labour could not fall below 30 per cent, add something for the Liberals – and the Nats were corralled, especially under proportional representation.

Labour insisted on PR for two reasons. First, they did not want the Nats to win a majority with 40 per cent of the vote. Second, they did not want Scottish Labour to win a majority with 40 per cent, and promptly introduce all sorts of socialist lunacy. London Labour was happy that its own northern supporters would be forced to govern in coalition.

Unfortunately, however, these Labour and Unionist devolutionists were guilty of a double overestimate: of the Scottish people and of the Scots Tories. In far too much of Scotland, the word "Thatcher" still provokes an intellectual and moral breakdown. Much of Scottish public debate on that subject is among the most shameful, self-pitying nonsense ever uttered in a supposedly advanced country. The cancer of grievance has destroyed much of Scotland's mental faculties.

Even if the Scottish Tory party were led by Adam Smith, Henry Dundas and Walter Scott, it would have difficulty in overcoming its countrymen's snivelling resentment. But the current leadership is some way below world-historical class. In the 80s and 90s, the Scots Tories produced Messrs Forsyth, Lang, Rifkind and Younger, plus my Lords Mackay and Strathclyde – as well as a score of able though less eminent figures. Today, most of their successors are dire, and proportional representation creates another obstacle to a Tory revival. Under PR, those at the top of the party's list are virtually guaranteed a seat, however badly the Tories do short of extinction, not yet a danger. In the Scottish Parliament, the Tory leaders enjoy status and income without having to fight for it. They have no incentive to resist genteel decline, and there is a further hazard.

When Labour dominated the Scottish executive, there was no equivalent of the prawn cocktail offensive that the Blairites launched to woo the City. Most Holyrood Labour ministers were surly, glottal-stopped, class-hating mediocrities. It was hardly surprising that businessmen who had dealings with them found the process deeply depressing, especially as everyone assumed that they and their ilk would be in power for ever. Now, however, the Nat ministers use the language of free enterprise. There has been a smoked-salmon canapé offensive. This has led a lot of Scots who are natural Tories to conclude that independence might not be too bad after all.

David Cameron will become Prime Minister of the United Kingdom. If he wants to leave office in the long fullness still holding the same title, he will have to do something drastic to save Scottish Toryism.

A propos of leaving office, Gordon Brown now has a problem with the Glasgow by-election. Does he campaign there? Even if he is willing, would the Labour candidate want him? The media will inevitably try to turn the contest into a referendum on Mr Brown's leadership. That is unlikely to shore up the Labour vote.

It is extraordinary that Mr Brown could not persuade Wendy Alexander to stay on at least until the by-election was over. She has been a hopeless minister, a truculent colleague and a useless leader. She might at least have tried to compensate for this by showing some gratitude to the man who made her political career. (No wonder they were drawn to one another. They are similar personalities.)

It would be an irony if Gordon Brown's leadership were finally wrecked on a Glasgow by-election defeat. But even if the seat is lost to the Nats, there would still be no mechanism to force Mr Brown out of office. Even so, two questions are being asked with increasing insistence. How much more can he take? How much more can his party take? This does not mean that Gordon Brown will go, but the lack of enthusiasm for his leadership in his own party far exceeds the Tories' feelings about John Major in his worst days.