David Cameron this afternoon hit back at growing criticism over his election campaign – vowing to carry on warning about Labour's threat to the economy. The Prime Minister this morning faced the first serious criticism of the campaign so far, as Tory donors rounded on the party's lacklustre message and failure to pull away in the polls. But a defiant Mr Cameron this afternoon pledged to continue focussing on bread-and-butter issues like jobs, business and childcare. Scroll down for video . David Cameron this afternoon hit back at growing criticism over his election campaign – vowing to carry on warning about Labour's threat to the economy . He told supporters in Somerset: 'If you want political excitement. Go to Greece. If you want more showbiz in this election. Go to Hollywood. 'But here and now in the UK I'm focused on something real – a stronger economy.' Mr Cameron insisted the economy 'excites' millions of people. He said he would campaign on 'more jobs, more homes, more business, more childcare, more security in retirement'. He said: 'I make no apologies for focusing hard on that which is central to everything. When you get a new job, a new home, get a new childcare place or start a new business… now that's truly exiting. 'And you only get these things with a strong and stable government - not one held to ransom. That's not the excitement 'Britain needs. That's not a risk Britain should take.' Mr Cameron's remarks comes amid claims senior Tory figures are already planning to make Boris Johnson the next leader. Some MPs are prepared to engineer a coup against Mr Cameron in the days after May 7 by submitting letters of no-confidence in him and planning a 'mass show of support' for the London Mayor if the Tories lose, the Sunday Times reported. One major donor, who declined to be named, told the newspaper: 'Boris is the only one who can win. Everyone knows what is going to happen in 10 days' time. If Dave doesn't make it we'll get rid of him.' The Tories have nudged ahead in the polls with less than two weeks to go until polling day, but Tories are increasingly concerned it may be too little too late . London Mayor Boris Johnson - appearing on the BBC's Andrew Marr show this morning, has distanced himself from claims that he is being lined up to replace David Cameron as Tory leader . Multimillionaire Tory donor Peter Hall, who has given almost £600,000 to the Tory party since 2005, meanwhile has criticised Mr Cameron's 'curious lack of energy and belief in his campaign.' He said the PM needs to raise his game and 'unleash visceral passion and belief in his vision of the future', 'get down and dirty', as well as showing 'he cares', if he is to win on May 7. 'If we don't have a Conservative government after May 7 it will be because of David Cameron. His decision not to keep those Ukip people in the Tory tribe was a key error. 'I see no powerful vision of the future provided by David Cameron. There is no clear considered view of where we are headed.' Mr Hall warned that Cameron's mantra as a sound steward of the economy 'is not enough to win the votes needed to win the election' and added: 'Some people are really quite resigned to losing and they are planning the next step. 'It's a horrifying prospect if we were to lose. How can we lose when so much is at stake and when we have such a strong hand?'
Prime Minister insists he will carry on focussing on economic message .
Mr Cameron has been criticised for running a lacklustre campaign .
Tory donors have backed Boris Johnson to take over if the PM falls short .