David Cameron is guilty of ignoring the needs of the country beyond the capital, according to Lord Mandelson.
Speaking at the end of this morning's Labour Party press conference, the business secretary said the Conservative Party leader was "looking down his toffee nose" at the regions.
He said that Cameron's dismissive reference to "regional stuff" showed his plans to curtail regional development agencies would cost jobs.
But Lord Mandelson denied the party was engaged in negative campaigning, telling journalists that the decision facing the country was "serious".
He was appearing alongside health secretary Andy Burnham and schools secretary Ed Balls.
Labour unveiled a new election poster this morning featuring a picture of David Cameron with the words: "If you're there for him, he won't be there for you."
The poster is a reaction to yesterday's Conservative manifesto launch and their "Big Society" idea.
Lord Mandelson said the choice facing the electorate was between "Labour empowerment and Conservative abandonment".
"It is not empowerment that David Cameron is offering," he said. "His idea of empowerment is to say to people 'Here you are, get on with running things for yourselves.”
"Having the government step aside and say 'You are on your own, do your best' will not be most people's idea of an unmissable opportunity."
The Conservatives have pledged to hand power back to people by making schools, hospitals and the police more accountable to voters.
Health secretary Andy Burnham said that the Conservatives were offering a "false prospectus of health" which would "take power off people and hand it back to the system."
He said the public would be left with a "DIY NHS" where people had to "fight for everything".
"How will it be a national health service if you have no national standards?" he added.
And schools secretary Ed Balls said that 38,000 jobs would be axed in schools under Tory spending plans.
There would be "excellence for all under Labour" and "excellence for just a few under the Tories".
Questioned by journalists at the press conference, Balls said the government should have enforced tougher regulation on the banks while both he and Gordon Brown were at the Treasury.
"We should, in retrospect, have been tougher on some of the investment banks," he said.
But he said that during his time as City minister 2006-07 he was "continually attacked" by the Conservatives and the City for being "much too tough, much too hard" with regulation.
Gordon Brown accepted today that it was a mistake not to have taken a tougher line with the banks when he was Chancellor.
"All the complaints I was getting from people was, 'Look you're regulating them too much'. And actually the truth is that globally and nationally we should have been regulating them more.
"So I've learnt from that. So you don't listen to the industry when they say, 'This is good for us'. You've got to talk about the whole public interest."
But Liberal Democrat Treasury spokesman Vince Cable said that saying sorry was not enough.
"It’s not enough just to hold your hands up and say sorry without having a plan for making sure that the same thing doesn’t happen again," he said.
"Gordon Brown’s admission that he was swayed by the pleas of the City shows the danger of Tory plans to base economic policy on the wishes of vested interests.
"The only people that we should be thinking about are the British people and what’s best for them."
