In a little square between St Andrews’ main boulevards a one-man silent protest was occurring in the midst of unseemly fervour. As Nicola Sturgeon approached shoppers, soliciting the names of babies and helping students to take selfies, a retired gentleman was sitting down defiantly, arms folded; the very picture of that studied insouciance that Scots effect when in the presence of glamour. On his right 100 or so gaily attired SNP supporters were preparing to greet their leader. Perhaps this gentleman, alarmed by this regrettable outbreak of enthusiasm, simply sought to uphold the Auld Grey Toun’s reputation for rectitude and caution. “Are you an SNP supporter, sir,” I asked him. “Certainly not,” he replied. “I am a Conservative, but next Thursday I’ll be voting for Labour to keep the Nationalists out.”

With days of the 2015 general election campaign remaining I had found my first tactical voter. This is a shy species of uncertain political heritage and unknown numbers upon whom the Labour party in Scotland may yet have to rely if they are to avoid the party’s biggest humiliation since its founding.

An independent opinion poll last week indicated that the SNP might take all 59 seats north of the border, while most others suggest at least 45 Nationalists will be heading to Westminster. How fraught relations with Labour then develop could decide the fate of the next parliament.

The day before, in Moffat, in the heart of Scotland’s only Tory redoubt of Dumfriesshire, Clydesdale and Tweeddale, “the most dangerous woman in Britain” had seemed on a mission to break the world record for most selfies in a day. In an upper room of the town hall I tried to focus on the source of the affection these people harbour for Sturgeon. As dozens of small children were pushed forward to meet her, she seemed like the glamorous auntie living in California of whom you have often heard but rarely seen, but who always greets you with gifts and kisses. In the ladies’ restroom of Glasgow’s Crowne Plaza hotel earlier in the week Sturgeon encountered another new experience. She was accosted by a cackle of robust Glaswegian women.

“They asked for a selfie,” said Sturgeon, “and of course, how could I refuse? They were delightful. I’d never before been asked for a toilet selfie before. Only in Glasgow … ”

The newspaper photographers, a grizzled band, have loved it. On the helicopter hop from Dundee to St Andrews on Friday, the Press Association’s man was favoured with a bat-squeak of femininity. When he signalled to her discreetly that her Karen Millen dress was perhaps riding a little high she rearranged it demurely before turning to me and saying: “The photographer is protecting my modesty, Mr McKenna.”

If Sturgeon does send a battalion of 40-plus MPs to London next week attention will, once more, focus on the performance of Jim Murphy, Labour’s leader in Scotland. Frankly though, there is little more that he could have done to stop this popular Nationalist surge. A desire by many of their traditional supporters to punish Labour’s conduct during last year’s independence referendum only partly explains the political and cultural phenomenon that has been occurring in Scotland.

The Sturgeon factor is also significant. There has been a major increase in the number of women engaged in politics and they regard Sturgeon as a role model as well as a politician. This is a woman whom many mothers are holding up as an example for their daughters. As such, her appeal now carries well beyond the political arena. She is a standard-bearer for causes that go beyond party politics. Thus, something more than mere politics may be required to dethrone her.