Has the No camp got it wrong? This may seem an odd question to ask when the unionists are still leading in the referendum race but there is no doubt that the gap between the two sides of the independence debate has tightened.

According to a new YouGov poll in the Times today, when the don’t knows are discounted, the No camp is on 58 per cent (down three points) and the Yes camp is on 42 per cent (up three points). A gap of 16 points is still healthy with six months to go but this is a considerable distance from the polls a year ago which gave the No camp a consistent lead of 20 points or more.

So it is now undeniable that the Yes camp has closed the gap on the No camp and, if this trend continues, then we shall be looking at a very, very close result in September. Better Together has spent the last month or two concentrating on business and economics.

It all kicked off with George Osborne’s declaration that an independent Scotland would be barred from sharing sterling with the rest of the UK – his ‘sermon on the pound’ as Alex Salmond cleverly dubbed it. This was followed by a raft of businesses, big and small, all warning of the perils of independence and threatening to decamp to England if Scots voted to end the Union. It culminated this morning with the CBI’s scathing attack on independence with John Cridland, the CBI Director General, hard-hitting warning that the SNP’s sums ‘don’t add up’.

But the problem for the No camp is this – it doesn’t seem to be working.

Everyone in Scotland now knows that business doesn’t want independence. It is as clear as day that companies all over Scotland and across the UK fear the disruption, the costs and the extra regulation that independence would bring and most are fiercely opposed to it.

Yet despite all these warnings, more and more Scots appear to be edging towards the Yes camp. Why is that?

One reason is because independence is becoming a financial and a class issue. Put bluntly, the poorer you are, the more likely you are to vote Yes and the richer you are, the more likely you are to vote No. The most committed Yes voters are low-paid or unemployed youngish men while the most defiant No voters are well-off women.

So, back to the original question – has the No camp got it wrong by expending all this energy on building a solid business case for the Union when the people who care about these things already support the Union? After all, the business case has now been won and it is likely that the vast majority of those connected with business, enterprise and corporate Scotland are now opposed to independence.

What the No camp has to do now is win over those who have been untouched and unmoved by the business case. It can do that – and there is also a belief in the No camp that the unionist vote will harden in the last six weeks of the campaign as more cautious Scots gravitate back to the status quo.

That may happen but Alistair Darling and the rest of the Better Together team have to find a way of moving on from the business arguments and connecting with those who, frankly, don’t give a damn what Standard Life, Shell or RBS have to say about independence.

They have to start winning back those women who like the idea of all the free childcare the Nats have promised to throw at them and those men who care more about what Neil Lennon, the Celtic manager, has to say than the thoughts of the Director General of the CBI.

That is their task for the next six months. It can be done but they will have to shift their tactics significantly to do so.

Tags: Alistair Darling, Better Together, Scottish independence referendum