THE result "is on a knife edge," declared Yes Scotland chief Blair Jenkins after the first poll since Monday's TV debate showed the No camp's lead slashed to just six percentage points.

The Survation poll, conducted in the wake of Alex Salmond's duffing up of Alistair Darling, put support for Yes on 47 per cent and No on 53 per cent after the don't-knows were excluded.

The company's previous poll, which followed Mr Darling's win in the first TV debate at the start of the month, had given No a much more comfortable 13-point lead. The news put the cap on what has looked like a bad week for the No side. Mr Darling's defeat - a disappointment if not a disaster -was followed by a less-than-successful campaign visit from the Prime Minister, who was told by the CBI that uncertainty caused by his plan for an in/out referendum on the EU was bad for business. Not exactly what he wanted to hear as he got to his feet to argue that "certainty" was one of the UK's big plus points.

In between times, Better Together was slated for a truly dreadful referendum video titled The Woman Who Made Up Her Mind, which was widely condemned as sexist and patronising.

So a cloud of gloom and rising panic hangs over the campaign's offices? Not a bit of it. Chatting to No strategists from the Conservatives, Labour and LibDems, it is striking how relaxed they are. Whether that's justified is another matter, of which more later, but Better Together firmly believes its campaign is going to plan. The chat is of a convincing win in the early hours of September 19.

Their confidence stems partly from their assessment of the Yes camp's position. Mr Salmond won Monday's encounter but "won ugly", No camp insiders say, with the kind of bulldozing performance that will have delighted his own supporters but have less appeal among the all-important undecided voters. They also believe the Yes campaign's all-out pursuit of the so-called "missing million", the folk so alienated by politics they never vote, is doomed to fail.

Yes Scotland and other pro-independence groups such as the left-wing Radical Independence Campaign claim they are making great strides in traditional working-class areas, helped by campaign messages about "job-creating powers" and protecting the NHS that are aimed at people in Scotland's most hard-pressed communities.

Campaigners on the ground are convinced there is a surge to Yes out there that isn't being picked up in the opinion polls but which could yet deliver victory. But Labour teams have been canvassing in many of the same places and, say insiders, the picture is different. They see no surge, certainly nothing on the scale required by the Yes camp to close the gap in the polls.

Better Together also believes its own strategy is the right one. It remains certain that highlighting concerns about the SNP's currency proposals is working.

The phrase "Plan B" is cutting through, No camp strategists say. On the doorsteps worried voters are bringing up the currency issue unprompted, they insist.

On that, they are reassured by Mr Salmond's obvious desire to move the debate away from his currency plans. In a tetchy interview the day after the televised debate, he berated Sky News's political editor Faisal Islam for pressing him to clarify his currency plans. "Get with the debate, man," he told him, clearly irritated by the line of questioning.

Mr Darling's attempts to pin down the First Minister on Monday night may have drawn groans from the audience, but the No campaign has stuck doggedly with the issue this week. It believes it is working.

Is it? There is a point in every campaign where those closest to it begin to believe their own narrative unquestioningly. Days before Labour crashed to defeat in the 2011 Holyrood election, a campaign co-ordinator was heard to say: "This smells like Glenrothes," a reference to his party's surprise by-election victory a few years earlier. He could not have been more wrong. Better Together's confidence may turn out to be blind complacency.

The feeling among most impartial observers is that the race is becoming closer, a hunch supported by yesterday's poll. We'll just have to wait for the next flurry of polls to get a clearer picture of who is right.