Nicola Sturgeon pictured at the Glasgow election count yesterday celebrating the SNP s success. Photo Colin Mearns NICOLA Sturgeon has vowed to hold another independence referendum if Boris Johnson refuses to agree to a new vote. The SNP leader underlined her position that if the Prime Minister fails to consent to a second referendum she would press on with plans to hold a new vote using Holyrood legislation. Speaking last night in a television interview, she said to stop the second referendum the Prime Minister would have to make a legal challenge to it in the Supreme Court. We would proceed with the legislation that is necessary and that is only happen if it was passed by the Scottish Parliament and then if he wanted to stop that it would be the case that he would have to go to the Supreme Court to challenge it and that would be his decision not mine, she told ITN.