Sixty years ago, Sir George Waters, legendary editor of The Scotsman newspaper, penned a thoughtful leader on the subject of Scotland's future: "A nation may live for long in unity with another nation without taking hurt . . .," he wrote. "But once self-consciousness creeps in and people begin to pry and question and to talk of rights and wrongs, the basis of trust has gone and something new must be put in its place."

Not much has changed since then. The Scots have been prying, and questioning the rights and wrongs of their relationship with England for much of this century. The demand for greater control over their own affairs has advanced and retreated down the years, but has never wholly disappeared. Now that demand is to be put to the test. On September 11th, a referendum will ask Scottish voters whether they agree that there should be a Scottish parliament and whether, in addition, it should have tax-varying power. So far, indications are that they will say Yes to both, but as the day approaches the arguments have grown more intense, and the anxiety of the devolutionists a little more marked. Things could yet go wrong.

The case for a Scottish parliament appears, on one level, to be incontrovertible. For nearly a generation, a large majority of Scots have voted for parties promising constitutional change and yet have won nothing. On the contrary, they have been governed, for the past 18 years, by a party whose policies they have specifically rejected. Under Margaret Thatcher, they were landed with the poll tax, which they detested, and a particularly authoritarian Englishness which got under their skin. In 1992 they voted massively for Labour, confident that devolution was virtually guaranteed. Instead, they got John Major, whose commitment to the preservation of the United Kingdom was, if anything, more passionate even than Lady Thatcher's.

For a time it seemed as if the stuffing had been knocked out of the devolutionists, while at the same time the setback failed to deliver more votes for the Scottish Nationalists - full independence has never commanded a majority in Scotland. But the return earlier this year of a Labour government committed to delivering what the late John Smith called "the settled will of the Scottish people" has finally brought the dream close to reality.

SO why the white knuckles, the little beads of sweat on the brows of Scottish ministers as the day approaches? It is because only now, in the run-up to the referendum, that the proposals for self-government have been subjected to detailed analysis, and that some of the cracks have begun to appear.

There is no lack of opponents ready to claim that those cracks are gaping fissures. On the one hand, the government's white paper, outlining the way a Scottish parliament will work, is as cogent and clearly set out a constitutional document as we have seen for a long time. It has sensibly taken as its starting-point the same arrangements that underpinned the Government of Ireland Act of 1920: it first defined the areas of responsibility that were still to be controlled from Westminster, then assigned the rest to Scotland.

The result is a major switch of power. This is no souped up county council, this is a genuine parliament with the ability to effect policy changes across a wide range. It preserves the United Kingdom but gives Scotland the ability to define its own identity within it.

On the other hand, the criticisms of the anti-devolutionists have grown rather than subsided. The first is the matter of how independent this parliament will be. Westminster, they point out, will still decide the size of the block grant to be assigned to Scotland. And though the formula by which it is calculated is well-established, the tap could easily be turned off sometime in the future if good will breaks down. Why, for instance, should English MPs continue to vote for a system that gives Scotland some 25 per cent more per head than their own constituents receive? What happens if the Scots start spending it in a way they strongly disapprove of? Why should a future Tory government not simply revoke the agreement altogether?

Then there is the famous West Lothian Question which hovers over the debate. Put simply, it asks why, in the event of a Scottish parliament, English MPs at Westminster should be refused any say over Scottish affairs, while their Scottish colleagues continue to be able to vote on English matters. The man who first framed it, the veteran Labour MP for what was then West Lothian, Tam Dalyell, has inconveniently persisted in asking it, and has been actively campaigning against his own government on the issue.

Finally, there is the vexed question of tax. Some time ago, it was decided that a future parliament should have tax-raising powers. A figure of 3p in the pound on the basic rate of income tax was mentioned, and this steadily became accepted as holy writ. The ability to raise tax became the virility symbol of the new parliament and Labour accepts that it must be retained.

The Conservative opponents of devolution leapt at it. Michael Forsyth, a previous Scottish Secretary, coined the phrase "the tartan tax" and predicted that it would drive business away. What, he asked was the logic whereby someone living on one side of the River Tweed should pay one rate of tax, while those living north of it should pay another.

In vain, Labour ministers pointed out that a tax would only be applied if a Scottish parliament voted for it. The electorate would decide, not them. It would, they said, be quite a small tax, and the white paper stipulated that it would never raise more than £450 million, a tiny proportion of Scotland's £16 billion budget.

But the issue has not gone away. In recent weeks, businessmen have weighed in. The Governor of the Bank of Scotland has warned that companies would cease investing in Scotland, that others would move south, and that the booming Scottish economy would be dealt a grievous blow. Interventions like this have ensured that the No campaign continues to hog the headlines, while press accounts of corruption in Labour-dominated councils in the west of Scotland have suggested that this will infect a future parliament.

Despite all this, polls continue to indicate that the Scots are not deterred. The last one to appear in The Scotsman showed that 68 per cent of voters would say Yes to the first question and 56 per cent Yes to the second, on tax-varying powers. The Scots are not averse to paying more tax if they think it will be sensibly spent, and they plainly believe that the kind of parliament they are to elect will use their money wisely. The remaining doubt is whether enough of them will turn out on the day to deliver a convincing result. A week, as Harold Wilson once said, is a long time in politics. In campaigning terms it is an aeon, and there is still everything to play for. But if George Waters' analysis is still as correct in 1997 as it was in 1937, Scotland will decide on September 11th that the time has finally come to put something new in the place of a constitutional system that no longer commands the respect or support of a large majority of its people.

Magnus Linklater, a columnist with The Times, is a former editor of The Scotsman.