Has Salmond given Yes the 'Big Mo'?

Three weeks ago, after the first debate between Alex Salmond and Alistair Darling, the First Minister woke up to some very bad newspaper headlines.

This morning it was Mr Darling’s turn.

In fact the headlines today for the former Chancellor after last night's exchanges between the two are, if anything, worse than those Mr Salmond faced.

There is near universal agreement that the First Minister came out on top this time. And some rather unflattering front pages.

The Sun headline, for example, is 'Not tonight, Darling'. Ouch.

Mr Salmond was more relaxed, more probing, more engaged and engaging with the audience at Kelvingrove.

It will be seen by some as a political trick, but he frequently stepped from behind his podium and spoke directly to the audience Mr Darling by contrast seemed at times edgy and ill at ease.

Whereas in their first encounter, he had pinned down Mr Salmond on currency his attempt to do the same again did not work.

The former Chancellor seemed a bit taken aback by the boos and jeers from audience in Glasgow.

It was said by some that the debate was bad tempered. Not so sure about that.

They two debated the big issues of independence - with some passion. It did get a bit pointed, even pointy, at times. But it's a debate which generates strong feeling.

But if Alex Salmond did win the debate - and an instant poll by ICM for the Guardian showed that's what voters thought - what impact, if any, will it have on the campaign in the remaining three weeks?Some facts. Even after Mr Darling was perceived to have won the first debate, the overall average of the Scotland-wide polls after that showed little shift to the ‘No’ campaign side after it.

And polling experts who have analysed last night's instant poll say that the debate last night had no immediate impact on referendum voting intentions.

You can see that analysis by Prof John Curtice here, if you want more detail.

But if - and it is still an if at this stage as there are polls to come - the debate does not shift voters, Mr Salmond’s performance has given a boost to the Yes campaign activists.

In American politics they often talk about the ‘Big Mo’ - momentum in the campaign.

The Yes side and the SNP believe last night's clashes has given them the Big Mo to make the final push to their hoped for victory.

On the other hand, the 'No' side say that despite the way the debate went - and they more or less admit Mr Darling had an off day - they still have the impetus.

Mr Salmond and the SNP have, in the 'No' side's view, still not answered key questions on the risk of independence and the currency and independent Scotland would use.Post-debate, the First Minister was today trying to say that the currency issue was now dead and buried.

The 'No' side do not see it like that. They believe the uncertainty over currency will - in their view - keep people in the 'No' camp.

Whether the boost to morale from Mr Salmond's 'victory' is enough for the 'Yes' side to overcome what the polls - if they are right - show is a still a substantial gap to close between now and September 18 remains to be seen.

And here's one other thing: don’t forget that the ballot papers will be rolling in as of the end of the week with up to a sixth of the electorate said to voting by post.

The referendum election is already under way even as the campaign reaches its final phase.