Nicola Sturgeon was booed last night as she refused to rule out holding a second independence vote in the next few years – despite having earlier claimed 2014’s referendum was a ‘once in a generation’ event. Two years ago, Miss Sturgeon said of the independence vote: ‘We have always said it’s a once in a generation thing.’ But last night, in an election debate on Scottish TV, she said she respected last year’s result, and said she would not call for another plebiscite in the SNP manifesto for the Westminster election in May. Scroll down for video . Support: Asked by Mr Murphy (left) where she 'wanted' Mr Miliband to be prime minister, Ms Sturgeon (right) said: 'I'm offering to help make Ed Miliband prime minister. I don't want to see the Tories in Downing Street' Power: The result of the election this May is set to put Ms Sturgeon in a powerful position at Westminster, with the chance of choosing which party can form a government. Above, the SNP leader at tonight's debate . She said she would not rule out such a call in the manifesto for the 2016 Scottish Parliament election, saying: ‘That’s another matter.’ The admission sparked howls of derision from the audience. The Scottish first minister was accused of holding Britain to ‘ransom’ after she said she was ‘offering to make Ed Miliband prime minister’. She said she wanted to wanted to do a deal with Mr Miliband so she can influence the policies of a Labour government and keep it ‘honest’. Reacting to Miss Sturgeon’s offer to prop up Mr Miliband, Labour’s leader in Scotland, Jim Murphy, said: ‘Nicola, we don’t need your help. Reacting to Miss Sturgeon’s offer to prop up Mr Miliband, Labour’s leader in Scotland, Jim Murphy, said: ‘Nicola, we don’t need your help. ‘What we need is people north and south of the border, people in Scotland, people in England and people in across Wales coming together to kick out an out of touch government.’ He pleaded with the audience to claim that Labour can only beat the Conservatives if people vote for Mr Miliband in Scotland. ‘Only Labour is big enough, only Labour is strong enough to beat the Tories and their austerity,’ he said. Debate: From left to right, Scottish Labour leader Jim Murphy, Scottish Conservative leader Ruth Davidson, First Minister and SNP leader Nicola Sturgeon and Scottish Liberal Democrat leader Willie Rennie . Plan: Speaking in the debate for STV, Ms Sturgeon (right) said wanted Scots to vote SNP rather than Labour because 'we can make sure Labour keeps its promises'. Left, Scottish Labour leader Jim Murphy . Grant Shapps, Conservative Party chairman said: ‘Tonight Nicola Sturgeon has promised that she’d prop up a minority Labour government – and hold Great Britain to ransom, vote by vote, policy by policy. ‘And that means more debt, higher taxes and the end of Trident – wreaking havoc on our economy and putting the security of British people and their families at risk. ‘Weak Ed Miliband doesn’t stand a chance. He’s in the pocket of Alex Salmond and Nicola Sturgeon: and you’ll pay the price.’ The SNP is way ahead in the polls north of the border, and Labour is expected to lose dozens of seats in May’s election. The result is set to put Miss Sturgeon in a powerful position at Westminster, with the chance of choosing which party can form a government. She said she would never prop up a David Cameron government, but would help Mr Miliband get into Downing Street. But she said the polls showed that Labour could not beat the Tories on their own. Speaking in the debate for STV, Miss Sturgeon said wanted Scots to vote SNP rather than Labour because ‘if there’s a strong block of SNP MPs, we can make sure Labour keeps its promises. ‘Tony Blair was elected on a wave of hope and optimism, but his Labour government began the process of NHS privatisation. ‘I don’t want to see a Labour government simply implement Tory policies. Heading for success: The SNP is ahead in the polls north of the border, and Labour is expected to lose dozens of seats in the election. Above, Ms Sturgeon, second from right, during the debate tonight . ‘We need to send a strong team to make sure Labour get it; so we can keep Labour honest.’ She said: ‘We will work with Labour to keep David Cameron out of Downing Street. Labour is not offering an alternative to Tory austerity. ‘I stood on a platform last week in the UK leaders debate with Ed Miliband and I heard Miliband say if Labour is elected and left to their own devices there will be further spending reductions. ‘I don’t want to see further spending reductions, I don’t think the country can afford them. That’s why we’re proposing modest spending increases and with SNP influence we can force Labour down that path.' The Scottish first minister has already said offered to work with Labour to keep the Tories out of power if this is possible in a hung parliament. ‘I’ve said to Ed Miliband and I’ll say to Jim Murphy this evening, that if there is an anti-Tory majority in the House of Commons after the election, even if the Tories are the biggest party we will work with Labour to keep David Cameron out of Downing Street.’ Asked by Mr Murphy where she ‘wanted’ Mr Miliband to be prime minister, she said: ‘I’ don’t want David Cameron to be prime minister; I’m offering to help make Ed Miliband prime minister.’ Mr Murphy replied: ‘Nicola, we don’t need your help. ‘What we need is people north and south of the border, people in Scotland, people in England and people in across Wales coming together to kick out an out of touch government.’ He claimed he believe Labour would win, saying: ‘Even when my football team plays Barcelona, I don’t expect us to lose. ‘David Cameron ain’t no Lionel Messi – he can be beaten. ‘Any seat that Labour loses in Scotland reduces the chances of Ed Miliband becoming prime minister.’ Scottish Tory leader Ruth Davidson said the SNP’s position – urging Scots to vote against Labour and also promising to prop up a Labour government – was illogical. ‘Vote for what you want,’ she said. Audience members attending live political events occasionally catch the eye of the public. And last night was no different as a man wearing a fake moustache during the Scottish leaders’ debate caused Twitter to erupt. The man was filmed wearing a thick fake black moustache and large fedora hat as the four main political parties took part in a televised TV debate. Many social media users posted pictures of the blond-haired man on Twitter and questioned the authenticity of his facial hair. Others started a campaign to find the unnamed man and used the hashtag #moustacheman. The identity of the joker was later revealed as a man named as Danny McAfee, the father of Jack McAfee, who tweeted a picture of him without the disguise. A photo also emerged of the man posing with Nicola Sturgeon after the debate. Moustache man: The man, dressed in fake facial hair and a fedora, was spotted in the debate audience . Social media frenzy: One Twitter user re-imagined the debate with an audience full of moustache wearers . Rumbled: The joker's identity was later revealed as the father of Jack McAfee, named as Danny McAfee . Time for a picture: After the debate, he was seen posing with SNP leader Nicola Sturgeon, pictured above .
Nicola Sturgeon took part in debate between leaders of Scottish parties .
SNP leader said she is 'offering to help make Ed Miliband prime minister'
Her failure to rule out another referendum was met with boos by audience .
Added she would not support Conservative government with SNP MPs .