Business leaders have voiced their fears over the 'disastrous Tory campaign' which they believe has been too focussed on 'personal attacks and scaremongering'. They expressed concerns over the negative tactics employed by the Conservative campaign ahead of the general election next month – which they believe have done little to discredit Ed Miliband. As it emerged that the Labour leader is now the bookies' favourite to be the next prime minister, a number of business leaders revealed they are worried David Cameron will lose the battle for Number 10. And it appears Mr Cameron's advisers have the same fear and have called on campaigners to change tack today. Scroll down for video . Business leaders have blasted the 'disastrous Tory campaign' which has focussed too much on personal attacks against the opposition. Pictured: David Cameron in Lincoln today (left) and Ed Miliband campaigning at Chatham House, London, today . Business leaders said Cameron's role in delivering economic growth had become the 'background noise' of the Conservative campaign when it should have been the focus . The critique comes just weeks after more than 100 of Britain's top business leaders backed the Conservatives' economic plan in what was described as an 'unprecedented move' urging voters not to risk a 'change of course'. In a notable intervention weeks from the election on May 7, the business chiefs, who run companies with well known retail brands such as Primark, Iceland, Ladbrokes and Costa Coffee, signed a better claiming a Labour government would 'put the recovery at risk'. But now, a number of FTSE 100 and other business leaders have anonymously criticised Mr Cameron's use of personal attacks on his opposition. Speaking to the Financial Times on the condition that they would not be named, one chairman said: 'The negative campaign has been disastrous'. Another added that the successes of the coalition government, including delivering real economic growth and jobs has become the 'background noise' of the campaign instead of its focus. But a Conservative spokesman insisted that the campaign's focus on the idea of the SNP in a coalition with Labour is doing well on the doorstep, according to the FT. Some argued the campaign's focus has been too narrow and that 'fear tactics' could backfire badly. 'The Scottish scaremongering plays into the SNP's hands,' said one chief. And it appears Tory tacticians had believed Mr Cameron's economic record would have delivered a solid poll lead by now. The polls put Mr Cameron and Mr Miliband on equal footing – and several business leaders suggest this is a result of the Conservatives underestimating the leader's appeal to voters. As bookies named Ed Miliband the favourite to be the next prime minister, one business leader said: 'Every time Miliband is visible, he appears credible' 'Every time Miliband is visible, he appears credible,' said one. 'The worst thing is when (Conservative) Central Office tries . to be helpful,' one Conservative candidate told Reuters. 'On the doorstep, when you speak to voters, very little is . changing. The campaign has been almost genteel.' Mr Cameron helped nurture a recovery that has lifted the . economy out of its deepest downturn since World War Two to give . Britain one of the fastest growth rates in the developed world. Lynton Crosby, Cameron's Australian election guru, has now told the Conservatives to focus on that. His philosophy, fellow advisers reveal, is that 'you can't . fatten a pig on market day,' meaning voters need to be bombarded . with a message well in advance of polling day for it to 'take.'
Expressed concerns over tactics employed by the Conservative campaign .
Labour leader is now the bookies' favourite to be the next prime minister .
'Every time Miliband is visible, he appears credible,' said a company boss .
Tory tacticians have now told campaigners to focus on economic success .