Labour's plan to balance the books
Labour would be a government of both change and "responsibility", Ed Miliband said as he launched a General Election manifesto centred on boosting voters' faith in the party to handle the economy.
In a bold bid to wrest the initiative on the key issue just five years after the financial crash helped push the party from office, he said it was the Tories making "unfunded, unfair and unbelievable" promises.
But political rivals said "nobody will be fooled" by the Opposition leader's commitment to cut the national deficit every year and not borrow any money to fund policy pledges.
Prime Minister David Cameron said it was "not a conversion, it is a con" and George Osborne said the "small print .. confirms that he will run a deficit every year which means higher borrowing, more debt and higher taxes".
The Conservative Chancellor seized on analysis by a respected thinktank which said Labour's spending plans would remain "a big unknown" until it made clear how fast it wanted to balance the books.
And Liberal Democrat Deputy Prime Minister Nick Clegg compared Labour's pledge on borrowing to a bottle-a-day alcoholic "saying they have no plans to drink more vodka" and said the document was "not worth the paper it's written on".
"It's a dangerous addiction and the Labour Party have no plan and no date by which to clear the decks, wipe the slate clean and deal with the deficit," he said.
Meanwhile, Mr Clegg set out a "red line" for coalition negotiations if the May 7 General Election results in a hung Parliament, insisting that he will not accept the £12 billion in welfare cuts over two years proposed by Conservatives.
Asked about the Tory target in an interview for BBC1's Leader Interviews, Mr Clegg - who has set out a £27 billion Lib Dem deficit reduction plan featuring just £3 billion of welfare savings - said: "I wouldn't accept that."
Pressed by interviewer Evan Davis on whether this amounted to a "red line" in post-election negotiations, Mr Clegg said: "In exactly the same way that I could never countenance recommending to the Liberal Democrats that we enter into coalition with a Labour Party that isn't serious about balancing the books ... equally I would not recommend to the Lib Dems that we go into coalition with the Conservatives if they insist on a plan which is wilfully a remarkable departure from what we've done in this coalition."
The Labour manifesto, launched in Manchester, contained a small number of new policies including raising the minimum wage to beyond £8 by 2019 and a one-year rail fare freeze paid for by ditching road schemes.
But its first page was dominated by the so-called "budget responsibility lock", guaranteeing every policy is fully costed and every Budget would reduce the deficit
Mr Miliband acknowledged that the task would not be "instant or easy" and acknowledged public doubts that see Labour well behind the Conservatives in polls on economic competence.
He insisted though that "this plan shows there is no trade-off between being disciplined and making a difference" and declared that he was "ready" to lead the country.
"And it is a manifesto which shows Labour is not only the party of change but the party of responsibility too.
"Everything in this manifesto is funded. The deficit will be cut every year. The books will be balanced and the national debt will be falling," he said.
He accused the Tories - who have pledged to meet in full the additional £8 billion a year the NHS says it needs by 2020 to survive - of trying to fund the health service "on an IOU".
Unlike the Conservatives and Liberal Democrats, who launch their manifestos later this week, Labour offers no timetable for clearing the deficit, saying only that it will get national debt falling and a surplus on the current budget "as soon as possible in the next parliament".
Mr Miliband said the coalition government had shown it was wrong to set "arbitrary" deadlines for deficit reduction - a stance which the head of the Institute for Fiscal Studies suggested left voters in the dark.
"The big unknown on the Labour side is how fast they want to get there and therefore do they need significant spending cuts or tax rises at all," Paul Johnson told BBC News.
While the policy was "entirely credible" it "could involve significant spending cuts or tax rises over the next three years if they want to get there within the next three years, or it could actually involve no spending cuts in order to just achieve that by the end of the parliament", he said.
Mr Osborne said: "We have a clear plan for the future and track record of success on the economy but Ed Miliband today failed to provide a credible economic plan for Britain.
"There were no new ideas for our country and if you read the small print, independent experts are already saying it means he will run a deficit forever."
The manifesto said Labour "will not compromise" over the economy - as the party faces the prospect of losing many seats to the SNP in Scotland and needing the nationalists' support to govern in the event of another hung parliament.
In a clear dig at the SNP, Mr Miliband said: "There are some parties in this election who are coming along and saying we don't need to make any difficult decisions, there needs to be no reductions in spending at all, it's all going to be easy. That's not the route we're taking.
"There are other parties...who seem to be supporting them - saying we've got to go even further than we've gone in this parliament, doubling the cuts next year and all of that.
"In the Conservative Party's case ... they're not only saying they'll make these extreme cuts but then they're also piling on £20 billion of unfunded commitments on top of it, which makes it completely the sums not adding up."
SNP leader Nicola Sturgeon said: "There is a very clear choice at this election: you can have more austerity with Labour, the Tories or the Liberals, or you can have a clear alternative to austerity with the SNP."
The minimum wage pledge goes beyond the party's previous promise to raise it to £8 an hour by the end of the next parliament in 2020 - which critics said it was already due to reach in any case.
Labour said it would mean an extra £800 a year for a full-time worker over and above Tory plans.
It said the £200 million cost of capping rail fares would be paid for by "delaying road projects on the A27 and A358, for which the economic case is still uncertain".
Mr Miliband's optimism was somewhat dented by a new poll showing the Conservatives moving into a six-point lead - with a score of 39%, the party's highest for more than three years.
The Tories were up three and Labour down two on 33%, according to the ICM survey for The Guardian conducted over the weekend.
Most recent polls have shown the main parties all-but inseparable though Labour had shown signs of inching ahead last week.
After one poll last week suggested Mr Miliband had also edged ahead of Mr Cameron on personal ratings, the latest findings showed the PM on a healthy +18 points with Mr Miliband languishing on -30.
On a campaign visit to a car parts plant in the Conservative marginal seat of Stockton South, Cleveland, Mr Cameron said: "What's striking is, Labour are committed to running a budget deficit forever. So this is not a conversion to responsibility, it is a con trick and more borrowing would mean more taxes.
"So, frankly, it's the same old Labour and the same old mess that they produced the last time they were in government."
In another comment seized on by the PM on Twitter, Mr Johnson told BBC's Daily Politics: "It gives them an enormous amount of flexibility ... but it really makes a big difference.
"There is a huge difference between £18 billion of cuts over the next three years and no cuts and literally we would not know what we were voting for if we were to vote for Labour."