George Osborne today refused to match Labour's pledge not to increase VAT as a row erupted over how to balance the books after the election. The Chancellor declined to give a 'cast-iron guarantee' to match Labour's pledge not to increase VAT over the five years of the next Parliament. It came after Labour's shadow chancellor Ed Balls that Conservatives had a history of raising VAT after elections despite saying they had no plans to do so during the campaign. Scroll down for video . Chancellor George Osborne declined to give a 'cast-iron guarantee' to match Labour's pledge not to increase VAT from 20 per cent over the five years of the next Parliament . Appearing before the Commons Treasury Committee, Mr Osborne was repeatedly challenged to match Labour's promise but refused to do so . Labour today unveiled a new poster warning of Tory VAT hikes after the election. The headline rate of VAT stands at 20 per cent after Mr Osborne increased it from 17.5 per cent in his emergency Budget in 2010. Mr Balls claimed that another rise after the election on May was 'the only way the Tories can make their sums add up'. Launching a new Labour poster, Mr Balls said: 'We will make our tax commitments in full in our manifesto. But I am clear that while millionaires have been given a huge tax cut, working people are paying more in tax after the last five years of the Tories. 'So, today, I can announce a clear pledge to the British people. The next Labour government will not raise VAT. And we will not extend it to food, children's clothes, books, newspapers and public transport fares. 'We will not raise VAT because it's the tax that hits everyone. It's the tax that hits you every day. And it hits pensioners and the poorest hardest.' In the Houses of Parliament today, Mr Osborne was repeatedly challenged to match the promise but refused to do so. Labour MP John Mann asked the Chancellor four times to give a 'cast-iron guarantee' that he would not hike the tax. A second Labour MP, Andy Love, also twice pressed the Chancellor over whether VAT would have to rise. Labour's shadow chancellor unveiled a new poster warning 'the Tories will raise VAT' to help balance the books . In his responses, Mr Osborne said he did not intend to increase the tax but stopped short of an actual pledge to rule it out. He told Mr Love: 'I have identified where the £30 billion of savings I believe need to come from and they don't involve a VAT rise. 'The question for those who say they are going to try to balance the books but say it mainly has to be done through tax, as the official Opposition does, has to spell out what those big tax rises are. 'And it's pretty clear today that they have opened to door to a big increase in National Insurance and the `jobs tax' and I think it would be very, very damaging for this country.' To Mr Mann, the Chancellor said: 'We don't need to increase VAT. I couldn't be clearer. We do not need to increase VAT because our plans involve saving money on the welfare budget and Government departments.' In a jibe at Mr Osborne's former membership of an Oxford University dining club, the Labour MP retorted: 'Your answers are more Bullingdon than Bassetlaw. In Bassetlaw, we like straight John Bull.' And reviving memories of Mr Osborne's 'omnishambles budget' of 2012, he offered the Chancellor a Gregg's pasty to give him the strength to respond more fully. Mr Balls claimed the Tories 'have a secret plan to raise VAT again' But Mr Osborne stuck to his position: 'The policies we have do not involve a VAT rise ... Our proposals, our spending plans, our policies, do not involve tax rises. They don't therefore involve a VAT rise. However, your proposals do involve tax increases. You have been quite open about that. That means it is either VAT or jobs tax or income tax. 'That's what people will get if they vote Labour. But of course they won't vote Labour because they remember what you did last time.' Mr Mann retorted: 'The pasty-eaters will beware again.' Mr Balls, who believes Gordon Brown's refusal to accept his calls for a pledge not to raise VAT contributed to Labour's defeat in 2010, said he would 'resign rather than break this promise'. Speaking in Birmingham - in front of a new poster featuring the letters VAT as concrete blocks with the slogan 'Don't let the Tories hit you with this' - Mr Balls said the unannounced rise from 17.5 per cent to 20 per cent after the 2010 election had cost families an average £1,800 over four years. It was put up 'despite David Cameron telling the British people a few days before the election that he had 'no plans' to do so and despite the promises of Nick Clegg', he said - and had been raised by every Conservative administration for 40 years. 'Now history is repeating itself all over again. It's the same Tory lie about VAT: 1979, 1992, 2010 and now 2015. 'Everybody in the country knows what it means: the Tories have a secret plan to raise VAT again.' Treasury figures suggested a rise to 22.5% would cost a family with children an average of GBP450 a year and a pensioner couple GBP275 a year, he said - something a Labour administration would not allow. A Conservative spokesman said: 'Ed Miliband and Ed Balls have repeatedly said they will raise taxes. It is time that they came clean with the British public about which taxes they will raise - income tax or national insurance? 'The choice at this election is becoming clearer by the day: sticking with the competence of the Conservatives' long-term economic plan that's securing a better future for Britain or abandoning that plan with hard-working taxpayers paying the price for the economic chaos that would result from Ed Miliband in Downing Street.' Liberal Democrat Chief Secretary to the Treasury Danny Alexander said: 'Labour have no credibility on the economy. Ed Balls might be ruling out a rise in VAT but he can't rule out a rise in National Insurance and already plans to hike corporation tax. 'Because the Liberal Democrats have taken the difficult decisions to stick to a balanced recovery, under our future plans there is no need to raise income tax, National Insurance, VAT or corporation tax.'
Labour's Ed Balls unveils poster warning Tories will hike VAT again . Osborne used first Budget in 2010 to increase rate from 17.5% to 20% . Chancellor insists his plans to balance books do not require new increase . But he repeatedly refused to match Labour's promise ahead of election .