UK 3 March 2017 Theresa May's Scottish referendum dilemma There are huge risks to allowing the SNP a second vote - and to denying one. Getty Images. Sign UpGet the New Statesman's Morning Call email. Sign-up From the moment that the UK voted to leave the EU, Nicola Sturgeon has talked up the possibility of Scotland voting to leave the UK. Support for independence is unchanged since the referendum but the SNP is undeterred. Some expect Sturgeon to demand a second vote as early as this month (coinciding with the triggering of Article 50 and the SNP's spring conference). After Theresa May's commitment to leave not just the EU but the single market, many nationalists believe that they will never get a better chance (Scotland voted Remain by 62-38). But if Sturgeon wants a second referendum, she will need May's consent. The power to stage a binding vote continues to reside with Westminster. But while there is no legal obstacle to May vetoing a second referendum, there is a political one. The sight of the government denying Scots another say could trigger a surge in nationalist support (prompting Sturgeon to stage an indicative poll). Though May has condemned the SNP's obsession with independence (as in her speech to today's Scottish Conservative conference), she has been careful never to rule out another plebiscite. Like David Cameron before her, the Prime Minister must weigh the risks of staging a referendum against the risks of not doing so. Scottish Conservative leader Ruth Davidson has argued that the Unionists would win a second vote by a bigger margin. But others on her side are less confident. Labour's polling position points to another decade of Conservative rule (a fact the nationalists will repeatedly exploit) and Brexit has strengthened the nationalist case (as Tony Blair recently conceded). Scottish Labour is a profoundly diminished force and the Tories, if no longer reviled, are far from adored. Though the polls haven't moved that isn't only a problem for the nationalists. The SNP needs a swing of just 5 per cent to triumph next time. Having eroded the Unionist lead in 2014, it would be reckless to assume the Yes side cannot do so again. Set against this is the collapse in the oil price and Scotland's vast projected budget deficit (which at 9.5 per cent is twice that of the UK). Brexit is also not an unambiguous good for the nationalists. More than 400,000 Yes voters backed Leave and a third have since defected to No (countered by 12 per cent who have moved in the opposite direction). Despite Brexit, the economic case for independence remains weak. Scotland exports four times as much to the rest of the UK as it does to the EU (£48.5bn to £11.6bn). But Brexit is also proof that political emotion can triumph over economic reason. And May would struggle to argue that Scotland should not leave its biggest export market while the UK does precisely the same. Cameron's fate demonstrates the perils of staging a referendum in the expectation that it will be won. As May knows, with Labour chronically weak, the greatest threat to her premiership is the SNP. › Will Alain Juppé run if François Fillon quits? George Eaton is senior online editor of the New Statesman. Subscribe For daily analysis & more political coverage from Westminster and beyond subscribe for just £1 per month!