Self-assured and poised in her stilettoes and new hairstyle, Nicola Sturgeon clearly revelled in being centre-stage – addressing a nationwide audience of Britons, rather than just the usual five million Scots. Such was her exultation that Judy Murray, mother of tennis star Andy (who was widely criticised for voicing his support for Scottish independence on the eve of last year’s independence referendum), tweeted about her triumph. Judy Murray said: ‘GSM Sturgeon’ (Game, Set and Match). Scroll down for video . The Britain-wide TV audience was clearly impressed - an instant poll by YouGov found that 28 per cent thought  Nicola Sturgeon was the best performer . For most people outside Scotland, this will have been their first proper view of Scotland’s First Minister. Until now, she had been in the substantial shadow of her noisy and bullish predecessor, Alex Salmond. But few north of the border were surprised by her performance. The fact is that Sturgeon has the most experience of governing of any of the seven politicians taking part in the TV debate, having been a member of the Scottish Cabinet and Deputy First Minister since 2007. Such is the hero-worship she attracts in Scotland, that even after the SNP lost the referendum vote last year, 12,000 people paid to see her speak at Glasgow’s Hydro, a concert venue more usually home to pop stars such as Sting or Rod Stewart. Sturgeon is a very canny operator. Her style on Thursday night was deliberately calm, natural and direct – qualities that are rare in politicians in this age of spin and slipperiness. The Britain-wide TV audience was clearly impressed. An instant poll by YouGov found that 28 per cent thought she was the best performer. Fascinatingly, one of the most-searched things on Google immediately after the end of the broadcast was whether people who don’t live in Scotland can vote for the SNP on May 7. I found myself torn. As a fellow Scot, I wanted to see her do well. But as someone who regards himself as ‘British’ and who voted to keep the union, I am all too aware of her determination to destroy my country. Indeed, Nicola Ferguson Sturgeon is a very dangerous woman. Such was her exultation that Judy Murray, mother of tennis star Andy, tweeted about her triumph. Judy Murray said: ‘GSM Sturgeon’ (Game, Set and Match) Leader: For most people outside Scotland, this will have been their first proper view of Scotland’s First Minister . Although poles apart politically – and Sturgeon herself would run the Royal Mile in Edinburgh at the comparison – she shares many similarities with Margaret Thatcher. Like Mrs T, the SNP leader transformed her image from that of a dowdy egghead into a glamorous, power-dressing imperatrix – emphasising a mixture of elegant feminine charm and steel. Her strength of character and willpower have driven her to the top of a party that has traditionally been dominated by powerful men in kilts. What has lifted her above these male rivals is her emotional intelligence. Although naturally shy, her two decades in politics has seen her grow into a polished public performer. Make no mistake, however: she is unequivocally left-wing. And she is also an avowed feminist. Indeed, during her SNP conference speech last month she said: ‘I am determined that – unlike that other woman leader we once knew – I will use my time in this job to improve the lives of women across our country.’ One of her first acts as First Minister was to create a gender-balanced Cabinet. First Minister Nicola Sturgeon greets young fans on the campaign trail in Edinburgh, where she was hailed as 'Scotland's Queen' Dangerous: SNP leader Nicola Sturgeon could hold the balance of power and be in position to decide who forms the next government . Having taken over from Alex Salmond after the SNP had lost the referendum, Sturgeon is in some ways exactly what Scotland needed. The country was – and still is – deeply divided and bruised by the vote. But the beguiling Sturgeon is a much more conciliatory and less arrogant figure than her predecessor. Very cleverly, she is now taking her Scottish independence campaign south of the border. And Thursday’s TV debate offered the perfect platform. By saying that her ‘message to the people of England, Wales and Northern Ireland is one of friendship’, it was a brazen charm offensive. Opinion polls suggest that post-May 7, Sturgeon could wield huge influence over who forms the next government in Westminster. And with predictions that her SNP could take 45 of Scotland’s 59 seats, there is a growing fear in England that she could hold Westminster to ransom. Range: Nicola Sturgeon, leader of the pro-independence Scottish National Party, was touted as one of the victors. Analysts remarked that none of the seven leaders delivered a 'killer line' to stand out from the rest . By propping up a Miliband government, she would try to impose her left-wing agenda: big-state socialism, ferocious opposition to an austerity programme, the non-renewal of the Trident nuclear deterrent, demands for expensive public spending projects that fly in the face of economic reality. If that happens, Britain would face a political crisis as the English (who number 53million) would feel justified in rebelling against a government that depended for its existence on the votes of a neighbouring country of just five million. Such a situation would, inevitably, become unworkable and collapse, with incalculable consequences for our political system. Of course, that would play right into the hands of Nicola Sturgeon. For she full knows that the growing anti-Scottish feeling in England could lead to Westminster concluding that the union with Scotland was unsustainable. Already, Scots are speculating that there would soon be a second referendum on independence. These are the cards that Sturgeon holds – and her hand is stacked with aces. The fact is that she commands her party and her nation in a way that David Cameron or Ed Miliband can only dream of. Today, Nicola Sturgeon is the most dangerous woman in British politics.
TV debate was the first proper view of Sturgeon for most outside Scotland . SNP leader has most experience of governing of  politicians who took part . Sturgeon is the most dangerous woman in British politics, writes columnist .