Salmond needs to accentuate the positives

So stands Scotland where it did? What is the state of play in the referendum marathon? The longest campaign in modern Scottish history really is almost over. In fact, the opinion pollsters say it already is, and that despite the optimism of the Commonwealth Games, Yes still hasn't a snowball's chance.

Professor John Curtice, the undisputed authority on Scottish opinion polling, says that the poll of polls stands at 57% to 43% against Scots voting to be an independent country. Who am I to argue? There has been, he insists, very little change in this ratio since the start of the campaign, and crucially, there have been no reliable polls showing Yes in the lead.

Only the Washington Post seems to think the result is too close to call, quoting a Southampton University academic who believes that the slow rise of Yes could rapidly accelerate in the final weeks. And curiously, the Unionist commentator Martin Kettle, in The Guardian, who says that the UK political establishment is "sleepwalking" to oblivion.

They'd better wake up to what's happening in Scotland, he says, or else Douglas Alexander could become PM of a broken Britain forced to join the eurozone. Well, it's the way he tells it.

But the majority view outside Yes circles is that the project is doomed. So, what can Yes do now to turn it around? After a bit of self-congratulation today, the Scottish Government will ­send a 12-page document to all 2.5 million homes telling them not to believe the Unionist hype. I'm not sure that will persuade many, but it's an important reminder that the formal campaign has only just started.

Everyone remembers the remarkable turnaround in 2011 when Alex Salmond overturned a similar poll deficit and delivered a landslide in the Scottish parliamentary elections. A referendum is not like an ordinary election, of course, but from now on the media coverage - at least on TV - will have to be pretty strictly balanced. This would tend to favour the independence campaign, which has had to contend with a largely hostile press.

On Tuesday, we'll see the first of many debates between Alistair Darling and Alex Salmond. (David Cameron is still refusing to play). It's impossible to say how this will go but on past form the First Minister should have a relatively easy ride. In fact, his main problem is likely to be over-confidence in the face of the Better Together chairman, who has a reputation as one of the dullest men in politics.

But these debates can sometimes throw up surprises, and Darling was, after all, the Chancellor of the Exchequer who handled the banking crash in 2008. So he is no fool when it comes to the numbers, which is largely what this campaign has been about. The press will be looking for a ''Salmond gets his comeuppance" story, so even a mediocre performance by Darling will likely be hailed a victory.

Salmond will have to try to get off the narrow issues of the currency, EU membership, pension deficit, declining oil revenues - where Darling is likely to be strongest - and paint a broader picture of Scotland as a potentially wealthy and egalitarian country held back by Westminster.

He will try to persuade Scots that this is a once-in-a-lifetime opportunity which they cannot afford to miss.

Not an easy task, since Scots have a tendency to look on the bleak side and have largely - according to John Curtice - accepted that independence is likely to have a negative impact on

their pocket. Few think that they will be £500 richer.

Salmond will also have to persuade Scots that they are not cutting themselves adrift from Britain, but seeking independence within the UK. No borders, no customs, no immigration controls, same passport. This is probably an easier case to make, not least because of the good-natured conduct of the Commonwealth Games, which shows that Scots and English people don't actually hate each other any more - if they ever did.

Unionist threats to erect border posts to keep immigrants out of England and pounds out of Scotland will, I believe, backfire since they only confirm the SNP charge that the Better Together campaign is led by Tories, Europhobes and bankers.

Throughout this campaign, it has been very much been the financial and political establishment that has set the tone and largely the content of the No campaign. Standard Life, Bank of England, Standard & Poor's, Insitute for Fiscal Studies.

Royal Bank of Scotland was at it again last week, saying independence would be bad for its business - though given RBS's tarnished reputation, it is surely an ally Better Together would be better without.

The warnings of economic catastrophe, lost pensions, hiked mortgages and flight of funds nearly all stem from George Osborne's Declaration on the Pound in March. The Conservative Chancellor effectively said he would wreck the Scottish economy by building a financial Hadrian's Wall to stop Scots using the pound - even though it is as much Scotland's property as England's.

So it's hardly surprising CEOs of firms like RBS, Sainsbury's, Aggreko, BP etc have been warning their shareholders about "instability" caused by "uncertainty" over the currency of Scotland. It's a self-fulfilling prophecy.

Most of the other indy scares have been pretty effectively rebutted. No-one seriously thinks Scotland would be barred from the European Union, or thinks Scots could not run a successful economy (even David Cameron agrees with that), or that Scotland would be left isolated and vulnerable to terrorists.

Looking back, many of the scares were ludicrous if not offensive: Scots being held at border posts, cancer research halted, Scottish children barred from the Great Ormond Street hospital.

Meanwhile, the Conservatives are providing the mirror image of Project Fear with their policies on the NHS, taxation, immigration, Europe, tuition fees.

Yes Scotland hardly needs to create any Union scares - the Daily Telegraph does it for them. However, while the Yes campaign and the Scottish Government have done much to defuse the various negatives about independence, there is still something of a credibility gap about the positives. In short, Alex Salmond has not finally persuaded Scots exactly what independence is for.

Self-government - of course. But many Scots feel they already have that with the Scottish Parliament. Not having any Tory governments - ditto. When it comes to overall economic management, the SNP has suggested very strongly that things would not look very different to today.

A common currency will involve ceding sovereignty to the UK Bank of England and possibly the Treasury, at least as far as controlling Scottish spending and borrowing is concerned. Pensions would remain on a UK basis as would things like energy subsidies, bank regulation, EU membership, research funding. The BBC would remain as would the Queen, defence co-operation, MI6, Nato, a shared British diplomatic infrastructure, the National Lottery ... it goes on.

I think the defensive argument for independence has largely been won - to save things like free education, a state-owned NHS, resisting Trident, the bedroom tax and the rest. What the Yes campaign needs to seal the deal is a clear and convincing vision of an independent Scotland, one that would fully justify the effort of building a nation.

Perhaps Scotland's buoyant artistic community, which seems set on turning the Edinburgh Festival into a Yestival, may be able to help here. Politicians dismiss the arts at their peril. Politics is not about numbers but the balance of hope and fear - and the quality of the political imagination.

Let's see what visions emerge in the next couple of weeks as the biggest arts festival in the world takes over the stage from the Commonwealth Games.