A senior Labour MP has admitted that the party would look to 'forge a common alliance ' with the SNP to ensure Ed Miliband becomes Prime Minister . David Lammy , who is standing for London Mayor , said the SNP was a party Labour could 'do business with ' in the event of another hung Parliament . The admission comes amid increasingly stark warnings from the Tories that the SNP will hold Labour to 'ransom ' if it holds the balance of power in Parliament next month . Scroll down for video . David Lammy , appearing on ITV News last night , said the SNP was a party Labour could 'do business with ' in the event of another hung Parliament . Polls suggest Nicola Sturgeon 's party are on course to win up to 50 seats on May 7 – wiping out any hopes of a Labour majority . But the Scottish First Minister has vowed to work with Mr Miliband to 'lock out ' David Cameron from Number 10 in exchange for higher government spending , more taxes and increased borrowing . Former prime minister John Major will today warn that Britain faces a 'daily dose of blackmail ' from the SNP if they have the power to bring down a Labour government . With 16 days to polling on May 7 , Sir John will say that a Labour-SNP administration would lead to 'weak and unstable ' government and wreck Britain 's economic recovery . Mr Miliband has ruled out joining a formal coalition with the SNP but has refused to be drawn on whether he could work with them on a vote-by-vote basis . However , speaking on ITV News last night , Mr Lammy went further – insisting that a deal with the SNP could be struck . Mr Miliband meanwhile has accused the Prime Minister of 'threatening the integrity of the United Kingdom ' by talking up the prospects of Scottish nationalists in the May 7 General Election . Speaking on Newsnight last night Mr Miliband insisted he would not form a Coalition with the SNP after the election . He said : 'We are fighting for a victory . I think we can win this election . But clearly , after the general election , you would forge common alliance with parties that you can actually do business with , and the SNP must be part of that story . ' It comes after Labour 's shadow House of Commons leader Angela Eagle said in the event of a hung parliament Labour 'would speak to any party that has got representation in the House of Commons in order to try to build a majority for a Queen 's Speech that the country desperately needs ' . Defence Secretary Michael Fallon said the admission exposed the threat posed by an SNP-Labour alliance . He told MailOnline : 'One of Ed Miliband 's most senior MPs is openly talking about forming a 'common alliance ' with the SNP . Nicola Sturgeon has called on Ed Miliband to forge an 'anti Tory ' alliance . 'The British public will pay through their noses for the higher taxes , the higher debt and the higher benefit payments an SNP-Miliband government will rack up . ' 'There 's only one guaranteed way to stop this – vote Conservative on May 7 . ' Speaking on the BBC 's Today programme this morning , the former foreign secretary William Hague said the Tories needed to 'sound the alarm ' over the threat posed by the SNP . He said : 'We have the danger here that people who want to break up the United Kingdom will be running the United Kingdom in a few weeks ' time if there is a Labour government with a large number of Scottish Nationalist MPs . 'And it 's not the Conservatives who have talked that up ; it 's the story , whether of opinion polls or of what everybody 's talking about on the ground . ' He added : 'Unless we have a Conservative majority we will be faced with a Labour government in a minority dependent on Scottish Nationalists , that they will make impossible demands , they will demand higher taxes , higher welfare spending , weaker defences every single day for five years and that will be disastrous for families across the UK and for the whole future of the United Kingdom . ' Mr Miliband meanwhile has accused the Prime Minister of 'threatening the integrity of the United Kingdom ' by talking up the prospects of Scottish nationalists in the May 7 General Election . Speaking this morning Mr Miliband insisted there would be no coalition with the SNP and denied Nicola Sturgeon 's party would hold the whip hand on policy , telling BBC1 's Breakfast : ' A Labour government led by me , what happens in that Labour government will be decided by me , not by the SNP . ' Labour had 'fundamental differences ' with the SNP , such as the nationalist party 's desire for a second independence referendum within five years , he said , adding : ' I 'm not having that . ' Mr Miliband said Mr Cameron had been 'talking up ' the SNP in the hope that it would take votes and seats from Labour north of the border and allow him to 'crawl back ' into 10 Downing Street . ' I think David Cameron is playing fast and loose with the United Kingdom , ' said the Labour leader . 'This is somebody who has given up hope of winning a majority . He is trying to boost the SNP . ' I think David Cameron is now threatening the integrity of the UK with the games he is playing . And I think Conservatives are now ashamed of what he is doing . '
David Lammy said the SNP was a party Labour could 'do business with ' Admission comes amid increasingly stark warnings over threat of SNP . Polls suggest the party is on course to win up to 50 seats on May 7 . John Major will today warn that UK faces a 'daily dose of blackmail '