The election starts here, as Cameron warns you could go to bed on 7 May with Nigel Farage and wake up with Ed MilibandDavid Cameron fired off much of his pre-election armoury on Wednesday, promising £7bn of tax cuts by 2020 aimed primarily at those on above average incomes and not backed by any new sources of funding.With his party still behind Labour in the polls and struggling to escape the shadow of Ukip, the prime minister closed a defiantly upbeat party conference in Birmingham by saying the next election will be fought on the issue of credibility and urging voters to trust his promises.