Rival economic policies continued to dominate pre-election political clashes after some of the country's leading businessmen endorsed Conservative plans to halt planned National Insurance rises.
Tory leader David Cameron hailed a letter of support from the bosses of several household name firms and the backing of major business organisations as a "significant moment" in the campaign.
But Labour suggested the plans could only be afforded if VAT was raised after the election instead, publishing a dossier setting out £22 billion worth of Tory policy promises it said were uncosted.
Mr Cameron's party claims it can pay to halt the bulk of NI increases for employers and staff due to come into force in April next year by cutting £6 billion of "waste" from Whitehall budgets.
Senior cabinet ministers ridiculed such efficiency savings as "illusory" - and angered some of the businessmen involved by accusing them of being fooled by "flimsy advice" and a Tory "deception".
Several hit back, insisting the planned hike would be a "tax on jobs" that would damage the economic recovery and accused Business Secretary Lord Mandelson of being "patronising" in his criticism.
Their stance was backed by business groups including the British Chambers of Commerce, British Retail Consortium and Confederation of British Industry who said the plan to axe some of the NI rise deserved "some credit".
Hailing their intervention, Mr Cameron said: "They are saying there is no threat to the recovery from cutting waste in 2010 but there is a threat to the recovery from putting up National Insurance contributions."
But Business Secretary Lord Mandelson said: "Mr Cameron and Mr Osborne are peddling a deception on businesses up and down the country and on the British people, and it's one that they are aware of. The truth is that this is a cynical deception."
Lib Dem leader Nick Clegg branded the Tories "the party of funny money and sums which don't add up".
