Ed Miliband will do 'more damage to the country than he did to his brother', Boris Johnson said this morning as the pair clashed on live TV. The London Mayor, who appeared alongside Mr Miliband on the BBC's Andrew Marr Show, launched a furious personal assault on his rival - with their encounter descending into a furious shouting match. But Mr Miliband, who beat his elder brother David to the Labour leadership in 2010, ended up laughing off the attack, responding: 'Come on Boris, you're better than that.' Animated: Boris Johnson wags a finger at Miliband, who appears to have a clenched fist, on the Andrew Marr Show this morning. The rivals' encounter quickly descended into a slanging match . No let-up: The Tory and Labour politicians go at it hammer and tongs in front of their TV audience . The heated exchange ends with presenter Andrew Marr (right) injecting and the men trying to laugh about it . Mr Johnson's verbal mauling of the Labour leader comes after the Tories were accused of 'descending into the gutter' for claiming that Mr Miliband may 'stab the country in the back' by doing a deal with the SNP to get into power. But today, Mr Johnson insisted that Labour could not take power without the support of the SNP, and claimed the prospect was 'actually deeply alarming'. He said Mr Miliband would have to take help from the Scottish party 'crouching on his back like a monkey' - making it impossible for him to govern in the interests of the whole UK. The London Mayor added: I am not saying that your brother had to present himself at A&E with a dagger in his back... [but] he [Ed Miliband] would do more damage to this country than he did to his brother, and that is the key point.' Verbal onslaught: Mr Johnson said that Labour could not take power without the support of the SNP . Time to go: Mr Johnson and Mr Miliband leave the politics programme after their massive on-air argument . Mr Miliband arrived at the BBC studios in Central London by car, while Mr Johnson cycled there . Ed Miliband won the Labour leadership in September 2010 by narrowly beating his brother David, who had been the runaway favourite for the top job. The younger sibling won the ballot by just over 1 per cent after the second, third and fourth preference votes came into play. David had garnered the majority of support from Labour MPs and party members - but Ed was ahead with the trade-union members. He hugged David after the result was announced - but later admitted the decision to stand against him caused deep division between the brothers. David stayed on as an MP until 2013, then announced he was quitting Parliament to become head of the giant New York-based charity International Rescue Committee. Mr Miliband hit out at the Conservatives for their campaign, saying: 'They are so desperate they are reduced to trying to set one part of the country against another.' Mr Johnson insisted the Conservative attacks on the SNP were not risking the union. 'I'm so proud and so positive about what's happening in this country at the moment, and I just think there are unnecessary risks involved in this Labour-SNP condominium,' he said. 'So the answer would be, no I don't think we are in any way imperiling the union. The people who would imperil the union, because that's what their party is called, is the Scottish Nationalist Party. 'And I imagine their strategy - like the parable, or the fable, of the frog and the scorpion - is to be allowed to be carried across the river and then ultimately to sting... [he is cut off]' The Conservatives have made the prospect of a Labour administration that's reliant on SNP votes one of the central planks of their election campaign in the last fortnight. But Mr Miliband has repeatedly insisted that he will not make any 'deals' with the SNP to become Prime Minister. And he told Andrew Marr today: 'No coalition, no tie-ins, I have said no deals - I have been clear about that. I am not doing deals with the Scottish Nationalist Party.' Asked explicitly whether he was ruling out a confidence-and-supply agreement, he replied: 'No deals.' Ed Miliband and Boris Johnson livened up the election campaign this morning when they went head-to-head on live TV. After being interviewed separately by presenter Andrew Marr, the pair of would-be Prime Ministers were brought together to challenge each other directly. Mr Miliband kicked off the heated exchange by demanding to know if Mr Johnson backed rules that allow wealthy foreigners living in Britain to avoid tax on their overseas earnings. He said: ‘Are you for keeping non-dom status? You’re defending those people who come here, they live here for 30 years, they are permanently here and they don’t pay taxes here.’ Mr Johnson responded: ‘Hang on, is this the Ed Miliband who was in the Treasury with Gordon Brown for about ten years? Are you the same creature? I mean, is there some sort of doppelganger going on?’ The Labour leader hit back, saying: ‘Don’t get rattled, come on now. Andrew Marr interjected to ask the London Mayor to defend inflammatory remarks in which he had accused Mr Miliband of being a back stabber. He said: ‘You attacked Ed Miliband very forcibly today, Boris, for backstabbing. Do you really think that is a fair approach to somebody who is standing in an election? Before Mr Johnson could speak, Mr Miliband said: ‘He doesn’t believe it. Come on, Boris, you are better than that.’ But the London Mayor replied: ‘I am not saying that your brother had to present himself at A&E with a dagger in his back. But he would do more damage to this country than to his brother - and that is the key point.’
London Mayor appeared with Mr Miliband on BBC1's Andrew Marr Show . Mr Johnson said Ed would damage UK more than he'd damaged his sibling . But he conceded: 'I'm not saying your brother had dagger in the back' Labour leader laughed off row, saying: 'Boris, you're better than that'