THE village of Dreghorn, Ayrshire, one summer evening in 1987. In her home, “Tulsa”, a bungalow down a quiet cul-de-sac, Kay Ullrich, a 43-year-old social worker and SNP ­activist, is preparing to go out canvassing. The prospect fills her with little joy. She has no chance of being elected MP for Cunninghame South. This is Labour ­territory of the deepest red, and any ­Nationalist chapping doors is likely to get a mouthful or worse. So when her doorbell rings, it offers a pleasant ­moment of procrastination, and she is intrigued to see a wee lassie on the front step. Sixteen years old, she appears much younger, and her first words are as surprising as they are welcome.

“Hello, Mrs Ullrich. My name’s Nicola Sturgeon. Can I help you in the ­campaign?”

Thus, did Scotland’s new First Minister make her entrance into public life. “So, this is The Room,” Ullrich says now, with kid-on reverence, showing the way to the lounge. “I should have a plaque up.” She remembers like it was yesterday. She asked Sturgeon in and signed her up to the SNP. “And she worked her wee butt off on that ­campaign.”

Five years later, aged just 21, Sturgeon was a candidate in her own right – standing in Glasgow Shettleston, another unwinnable seat, a blooding some saw as an anointment. Ullrich spoke at her adoption meeting. “I said, ‘This girl will be the first ever female leader of the SNP.’ I was absolutely certain of it.”

When, later this month, Sturgeon is sworn in as not just the first woman to lead the party, but the nation, Ullrich could be forgiven for standing up in the Holyrood gallery and declaring, loudly, proudly, “I told you so.”

Sturgeon, for her part, recalls the ­occasion vividly. “I was a shy teenager so it was a big thing for me,” she says. “I’d been trying to pluck up the courage for a long time … I didn’t know what reception I would get. Did they want a 16-year-old hanging about? I wasn’t a naturally extrovert teenager. My instinct would be to sit in my room and watch the election on telly. You know, I could easily not have decided to take that step. But I did, and the rest is history.”

Indeed. Twenty-four years from Tulsa, in 2011, Sturgeon found herself second-in-command in a majority SNP government with a mandate to seek a referendum on independence. Now, with the disappointment of that referendum behind her, she is standing on another threshold: the brink of power.

She admits to feeling, in this pivotal time in both her own life and the life of the country, a mix of trepidation and pride. We meet in her Scottish Parliament office. A Simpsons-yellow map framed on a wall shows all the SNP constituencies. A rosy apple on her desk suggests a gift left for a favourite teacher. She is wearing a red jacket over a black dress. Aged 44, she appears neat and poised; precise in speech. Her excellent hairdo brings to mind Rod Stewart (a favourite) in his early mod pomp.

This is a tremendous moment for her. Membership of the SNP has more than tripled since the referendum, polling suggests Labour could be all but wiped out in Scotland next year, and her personal approval ratings are shooting through the glass ceiling that she so ­recently shattered. Having been unable to secure divorce from the UK – which she took hard at first as a personal failure – she can at least console herself with this honeymoon, the most grandiloquent manifestation of which is her six-date tour of Scotland, including a forthcoming appearance at the 12,000-seat Hydro in Glasgow, a venue she is said to have sold-out faster than Kylie Minogue.

These appearances are, arguably, evidence of an emerging Cult Of Nicola in which she, not the party, becomes the ­focus of the faithful. Certainly, the decision to sell Sturgeon-branded merchandise has raised eyebrows. Hubristic or pure gallus? “Neither, actually, because it wasn’t my decision,” she replies. “Let’s just say I’m tholing the T-shirts.”

They are selling well, she’s told. But the figures which interest her more are in a recent poll suggesting that if a referendum were held again now, a majority – 52 per cent – of Scots would vote Yes. Sturgeon says she will decide in the latter part of next year whether there will be a commitment to another referendum in the 2016 manifesto. She would like to deliver independence as First Minister, but says she would be content – “if that’s how it pans out” – to govern as best she can without it.

What about Westminster? If there is a hung parliament in 2015, would her ­party come to an arrangement with ­Labour? “Anything’s possible. Well, not anything. We would never go into ­coalition with the Tories or prop them up in government.” She pauses, considers. “I wouldn’t rule out a coalition with Labour. We’d judge it on the basis of what we thought would give Scotland the best influence and the strongest voice. Something short of a ­coalition might be a better option – ­issue-by-issue support.”

Might partnership with Labour be a good way to secure a further referendum? In fact, she believes her government could stage another without Westminster agreement. It is in such hardball, square-go politics that her roots express themselves most forcibly. “There is a bit of a thrawnness and determination to plough your own furrow that comes from that Ayrshire character,” she says. “I’m Ayrshire born and bred and that’s definitely in me.”

Sturgeon was born in the summer of 1970 and lived in Prestwick until she was one, after which the family moved to Dreghorn. She is the elder of two daughters by five years. Her father Robin is a time-served electrician who works as an engineer with a security firm. Her mother Joan was a stay-at-home mum and is now provost of North Ayrshire. Mother and daughter remain close. Nicola still phones Joan every night.

The family home was a terraced house purchased under the right-to-buy scheme. The Sturgeons were SNP voters, but not activists, and politics was hardly the talk of the teatime table. That said, Sturgeon’s earliest political memory – “no more than a sliver” – is coming downstairs on the morning of 2 March, 1979 and hearing her parents discussing, despondent, the result of the devolution referendum.

“She was a quiet and studious child,” Joan Sturgeon says now. “She loved books from a very early age. She read ­before she went to school. Nicola was desperate to learn. She got quite ­frustrated, so we sat with her and she was easy to teach. Nicola would lift a newspaper at the age of four and try to read it.”

Interviewers seeking hinterland are, invariably, offered her “voracious” ­reading habits as evidence of life outside politics. They sometimes declare themselves disappointed with this, reading being the interest one adds, in brain-racked desperation, at the foot of CVs and lonely-hearts classifieds. Yet her deep love of books provides a glimpse of character: interior; introverted; interested in the lives of others yet not entirely at ease in the living crowd; in regular need of quiet contemplation and consolation. Books were an escape, an adventure, and they are still.

When, in her teens, she read Lewis Grassic Gibbon’s Sunset Song it felt in harmony with her emerging nationalism. “It seemed to speak to me at a time when other things were taking shape in my head.” No doubt she saw something of herself in the novel’s heroine, Chris Guthrie, in love with formal learning, but smitten, too, with the beauty and sweetness of the land and language, her place and its people.

Gillian Owens, an NHS phlebotomist, remembers herself and her big sister as very different children.

“Nicola and I played together but we were like chalk and cheese. I was into dolls and everything girly; Nicola was into sitting reading. She did once cut the hair off my Sindy doll, just for fun. I was a lot quieter. She was a very strong-minded wee girl. I would just do what I was told. I didn’t like getting a row. But Nicola would challenge.”

Wasn’t she shy? “She still is. Nicola can stand up in front of a load of folk and she’s great at what she does, but put her into a room down here with a few friends and she’s quite a shy person.”

Sturgeon loved music: Limahl and Wham! and, later, Letter From America by The Proclaimers, which she played incessantly, driving her parents daft. Did she have pop stars on her bedroom wall? “No,” says Gillian. “Nicola had posters of Jim Sillars, and CND badges. She had the Limahl haircut at one point.”

School was Dreghorn Primary and then Greenwood Academy, where she ­excelled. Her modern studies teacher, Roy Kelso, was a strong influence, encouraging and deepening her interest in politics and current affairs. “I remember writing in her sixth-year report that Nicola was like a good quality red wine that matured with age,” he says.

Irvine in the mid-1980s was struggling. The miners strike hit Ayrshire hard, and there had been a string of industrial closures. One account of the Irvine area in 1987, the year Sturgeon joined the SNP, noted that 12,000 people were unemployed and the dreams of those who had moved from Glasgow to the New Town were going unfulfilled. Families queued for emergency dole ­payments and at soup kitchens.

Sturgeon saw the impact of deindustrialisation – “Irvine no more,” in the words of the song – on the families of classmates. “That was the genesis of my political involvement,” she says. “The feeling that I remember most from back then – and I felt it personally – was a fear that pervaded the whole community, the fear of unemployment. My dad never did experience this, thankfully, but there was a sense then that if your dad was made redundant, that would be it – he might never, ever get another job and would be on the scrapheap. I remember being very angry, surrounded by people at school who had no guarantee of ­leaving to do anything other than go and become unemployed.

“Thatcher was the motivation for my entire political career. I hated everything she stood for. This was the genesis of my nationalism. I hated the fact that she was able to do what she was doing and yet nobody I knew in my entire life had voted for her.”

Teenage life continued. Homework. Pop music. Saturday night trips to Frosty’s ice disco at the Magnum Centre. Yet there was now this new element, which would come to dominate: the Scottish National Party. Never Labour. You voted for them and you still got the Tories. Independence seemed to offer a solution.

Ricky Bell, a friend who owns a Glasgow cafe, first met Sturgeon at this time. He was delighted that someone else of around his age, someone who shared his left-of-centre views, had become part of the local campaign. They were kids with a crazy dream. The SNP was far from the mainstream party it is now, especially in Labour-dominated Ayrshire. Saving your deposit was grounds for celebration.

“If you went to ten doors where folk didn’t shut it in your face then you’d had a reasonably good night,” Bell recalls. “It was a school of hard knocks in terms of learning your politics. But Nicola was ­always arguing that if we just chapped another few more doors, we might reach another few voters. She was often the one who would say, ‘Let’s just do another half hour,’ when the rest of us were ready to give up and go to the pub. She has a very strong work ethic. She never stops. How Peter ever sees her, I don’t know.”

“Peter” is Peter Murrell, chief executive of the SNP. He and Sturgeon have been married since 2010 (wedding cake by Tunnock’s) but together for more than ten years.

“Nicola’s family and close friends were hugely relieved when she and Peter became a couple, because finally she found someone to look after her,” says Bell. ­“Peter’s got a hugely important job in the SNP, but he’s no limelight-chaser, and I think it would be difficult for her to have a relationship with another very prominent politician.

“Also, I think a lot of her personal life is organised by him. It’s become a standing joke that there are no skills that Peter doesn’t seem to have. He cooks; he does all sorts. That’s allowed her to relax more. To have someone in her life that she loves is great for her, someone to share some of the burden. Peter understands the pressure, the issues, and can give counsel and advice.”

She and Murrell do not have children. People sometimes talk about the “personal sacrifice” she has made in her drive to change Scotland, by which they mean motherhood. “I don’t see it that way,” she says. “That would imply I’ve taken a conscious decision to sacrifice one aspect of my life to do other things. Things happen in life, and sometimes things don’t happen in life. It’s never been a conscious decision that I’m not going to have children because I want to become First Minister. That would be a very clinical and very cold thing to do, and that’s not how it’s happened.

“I also don’t see what I do as a sacrifice in any way. I’m about to do a job that will be hard work and challenging and difficult but, my God, it’s the biggest privilege anyone can dream of, having the chance to lead your country.”

The country’s relationship with her is casual, familiar; we are on easy terms. She is seldom “Sturgeon”, usually “Nicola”, sometimes “Wee Nicola”, or, to give that soubriquet its full expression – “Cannae stick that Alex Salmond. I like Wee Nicola, but.”

It is difficult to understand why this has happened. After all, though Sturgeon has become a constant presence in the media, most Scots have no clear idea of who she really is deep down. The companionable way people feel about her seems based on instinct – a sense that she is one of us. The curious thing about that is that she is really not. Sturgeon is an outlier, a prodigy, an alpha female who, from childhood, was set upon political success. As an individual she is remarkable, but it is as a type that we recognise her: the clever girl from the small town; the lass o’ pairts; sensible, dutiful, a grafter. She has a great appetite for hard work, a quality she says is “driven by the working-class, very Scottish fear of failure”. Her ability to absorb detail is said to set her apart from Salmond, a much more improvisational performer, and he, too, seems to respect this quality in her. This meant that the apprentice could, on ­occasion, instruct the master.

“She had the ability to hold her ground and influence him in a way that other ministers didn’t,” one civil servant recalls. “There was one particular issue around swine flu where he was asking officials who had been working for 36 hours straight to go and find some information that wouldn’t have made much difference. Not in the meeting, but outside of that, I heard her have a conversation with him where she said, ‘Look, it’s not on. You know that it’s not a priority.’ And that changed his reaction.”

Following Glasgow University and six years as a solicitor, the final two at Drumchapel Law Centre, working to prevent impoverished clients from being evicted, she won a Scottish Parliament seat in 1999. She was first a list MSP and now represents Glasgow Southside. Her transformation at Holyrood has been remarkable. Once perceived as cold, severe and distant, she is now the party’s warmest communicator. Still, “Nippy Sweetie” is the nickname which has stuck. It was first said, in a newspaper article, by Jamie Webster, trade union convener in the Govan shipyard, who explains now that, “I actually called her ‘a nippy sweetie and an able yin’. It’s very ­Glaswegian. ‘Nippy sweetie’ means ‘right in your face’ and ‘able yin’ means ‘right up for it’. It was a compliment and I stand by it.”

Not everyone is complimentary. The depute leader of the SNP is responsible for developing policy, and critics argue this process has become increasingly top-down under Sturgeon, with ordinary members and even MSPs who are not part of the inner circle finding it difficult to shape the agenda. The unease over the decision to endorse Nato membership is said to be much more widespread than acknowledged publicly and an example of what some regard as a willingness by the leadership to put politics above principle. “The other issue is that Nicola has been distant from many people within the party,” says a senior insider. “She comes over personably at public events, but the majority of back-benchers have very little contact with her.”

One long-served SNP councillor who has known Sturgeon for many years goes further. “Whatever she wants, she gets. They don’t call her Nasty Nicky for ­nothing. Don’t stand in her way or you’ll regret it. You have to come round to Nicola’s way of thinking.”

And if you don’t? “Your career would be finished. If you were up for reselection, she would make sure you weren’t.”

The weeks and months ahead will ­require finesse from Sturgeon as she balances a need to harness the energy of new members while not being so restraining that they bridle. Local branches of the SNP across Scotland are reporting hundreds of new faces, bodies packed into community halls, and there is a degree of nervousness among sitting MSPs that some of these newcomers, hot from the Yes campaign and surrounded by allies, might fancy themselves in ­Holyrood, pushing a radical independence agenda.

At a recent branch meeting in Edinburgh, there was talk of civil disobedience and unilateral declarations of independence; one man stood up and argued: “If you carry on business as usual, your new members will desert you. Why are we sitting discussing things when we should be out feeding the poor?”

Sturgeon, thus, finds herself at the head not just of a political party but a popular movement. Her challenge will be to satisfy the new urban lefties while not alienating the SNP’s traditional middle-class support. What will Sturgeonism look like? She is determined to make tackling inequality the defining feature of her First Ministership.

“I think about my own life story,” she says. “I grew up in a working-class family in a working-class area, and was the first member of my family to go to university. Not everybody can go on to become First Minister of their country, obviously, but I got to fulfil my potential. And yet my story is still the exception for people from my background. So we’ve got to have an iron focus on trying to do something about that.”

It will not be straightforward. She has disadvantages that her predecessor as First Minister did not face. Some critics argue that her strategic political brain is not quite as sharp as Salmond’s, others that her natural caution means she can take too long to make decisions. She will have to cope with increasing austerity. And her biggest day-to-day challenge is that Nicola will not have a Nicola – no profound relationship with a brilliant deputy.

Brilliant but not infallible. There have been missteps, notably the letter she wrote asking a court to be lenient on a constituent who had committed benefit fraud, for which, in 2010, she apologised to parliament.

She is said to be good in a crisis, but how she will cope with the pressures of ultimate leadership remains to be seen. As someone with a tendency to internalise feelings and to be extremely self-­critical, she can find politics wounding. She is understood to have felt a sense of personal responsibility for the 2008 Clostridium difficile outbreak at the Vale of Leven hospital, which cost the lives of 18 patients, while she was health secretary, her upset intensified by the fact that her own grandmother had, some years previously, contracted the superbug during her final illness.

One of the most frequent historical criticisms is that she is emotionally remote and lacking in empathy. What seems true is that she is much more at ease with “ordinary” folk than with what one former staffer calls “metropolitan, intellectual, grey-men-in-suits types” – in other words, the professional political class she now heads.

Some digging reveals evidence of a ­little-seen tender side.

Tommy Whitelaw, from Cardonald, is a dementia campaigner who had a number of meetings with Sturgeon as health secretary. He cared for his mother, Joan, until her death at the end of September 2012. That August, Sturgeon had contacted him to ask whether she could visit. No press, no officials, just her. “So, Nicola came to my house,” he recalls. “My mum was very poorly. She couldn’t walk, could hardly talk. But there was an absolutely incredible moment.” Sturgeon sat by the bed and held Mrs Whitelaw’s hand; she told her how proud she was of Tommy’s work and that her mother was called Joan, too. Mrs Whitelaw smiled at that and counted to five on Sturgeon’s fingers.

“I had been desperate to hear my mum’s voice again,” says Tommy. “That was just magical. It was Nicola Sturgeon the daughter, not the politician, who knocked on our door that day. And I was so glad to meet her.”

Sturgeon is, no doubt, a ruthless political operator who has fought and schemed to get to the top, and of course she is at the centre of a spin machine designed to keep her there, but she is also a real person – and it shows.

It will be fascinating, then, to see how she inhabits the role of First Minister. Alex Salmond loved wearing the crown; Sturgeon will be far less imperious, friends say. She has little taste for pomp and flummery, and looks aghast at the idea that, as a less divisive figure than her predecessor, she could become a Merkel-ish Mother of the Nation. It feels significant she intends to use the official residence Bute House for wining and dining but will not live there. Glasgow is home and she is a homebody. She enjoys spending time with her niece and nephews, going out for pizza, watching River City. None of this is exciting, but people can relate to it.

And how. The next time I see her it is in front of 2,000 people in Dundee’s Caird Hall on Friday night. She speaks for 30 minutes, takes questions for an hour, enjoys two standing ovations, and spends a further half hour smiling for hugs and selfies. OK, it’s a partisan audience, but this is remarkable: a genuinely popular – nay, adored – politician at a time when that profession is distrusted, even loathed. The memory that lingers, though, is not the cheering punters, but rather a quieter moment just before she went on stage.

Sturgeon stood in the darkened wings, head bowed, arms folded, the spotlight leaking through a gap in the curtain and edging her silhouette in silver. She could once again have been that nervous wee girl on the doorstep in Dreghorn, about to take the first step into a new life, the next step towards a new nation. Then she walked out on to stage, into the noise and light, in her red high heels, full of confidence and hope, and it took me back to something Jamie Webster had said when we spoke in the Govan shipyard.

“Could Nicola be the one?” he wondered when asked whether his nippy sweetie might lead Scotland to independence after all. “Well, I pose the question, ‘Why could she no’ be?’”