As the independence campaign’s first debate defied expectations, Darling has come away with a decisive, if surprisingly passionate, victory.

Last night’s STV debate between Alex Salmond and Alistair Darling did not follow the stereotypes that have built up around both men.

Darling – billed as the “bank manager” beforehand – belied his reputation as “the calmest man in politics” with an animated performance in which he peppered the First Minister with sharp one liners.

Salmond – normally heavy on the soaring rhetoric and Robert Burns quotes – was more understated than many had expected and instead tried to pursue forensic lines of attack to coax the former Chancellor into admitting that Scotland could comfortably succeed as a small independent state.

As the styles did not match expectations, neither, for many, did the outcome. A snap ICM poll for The Guardian found 56% of viewers gave Darling the win, as opposed to 44% for Salmond. With the Yes campaign still behind in the polls, this will have been a bitter disappointment for those who had hoped that a decisive Salmond victory would inject vital momentum for the final 6 weeks of their campaign.

The headline figure masks a number of even more interesting findings within the breakdown of the ICM poll.

Darling was considered the winner by viewers in every region of Scotland, suggesting a relatively consistent picture across the country. He fared particularly well in the Lothians (60%) and the Highlands & Islands (58%).

Alex Salmond fared better among female voters than male, with 48% of women giving him the edge compared to just 38% of men. This is particularly surprising given that support for independence has traditionally been lower among female voters. Perhaps the First Minister’s decision to adopt a less bombastic tone was successful in this regard.

The youngest age bracket (17-34 year olds) gave Darling a 60-40 win, with a similar proportion of 55 and overs giving the Better Together the edge. Alex Salmond edged it among the 35-54 year olds by 52-48.

Offering the greatest encouragement for the Yes camp are the views of undecided voters. Those undecided pre-debate gave Salmond a 55-45 win, while those still undecided post-debate gave him a 74-26 advantage. These are small samples, but nonetheless will be of some consolation to the SNP leader that all is not yet lost.

Nevertheless, the overall mood in the Yes camp is likely to be one of considerable disappointment today. After two and a half years we are finally entering the ‘short campaign’ period, during which those backing independence will need to make up considerable ground. This did not feel like a moment that will set them on their way to doing so.

Alistair Darling and Better Together would have settled for a score draw beforehand (or indeed a no-score draw), and he certainly got at least that. Those who had warned against underestimating the debating skills of the highly experienced ex-lawyer will feel vindicated today, though the No camp should continue to resist the temptation to be complacent.

In the aftermath of this debate it is likely to be a case of ‘as you were’. It is questionable how much such televised debates influence electoral outcomes even at the best of times. In this instance both men probably succeeded in shoring up their core support, but most likely fell short of making a decisive play for undecided.

But that will be enough to leave Alistair Darling much the happier with his night’s work.