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The gulf between Labour and the Conservatives deepened this morning as Alistair Darling, the Chancellor, defended his $20billion plan to boost the economy as recession looms while George Osborne, the Shadow Chancellor, derided it as a massive and unjustified gamble.

The pair went head to head in a round of radio and television interviews, justifying their stance and trading blows from afar on who would be worse off once tax rises to pay for the stimulus package kick in.

Mr Darling said that it would be wrong to leave people to sink or swim like the Tories did in the recessions of the 1980s and 1990s - while Mr Osborne said that saddling the nation with £1 trillion of debt would hold back any future economic recovery.

"I think there was a big intake of breath by the nation when they realised what the cost of the last 10 years was and that we are all saddled with a truly huge debt," Mr Osborne told BBC Radio 4.

Minutes later, Mr Darling told the same programme: "I'm not prepared to just let the recession take its course. In the 1980s and 1990s people paid a high price for that, and I'm not prepared to go down that road again."

Mr Osborne claimed that lower and middle income families earning £19,000 or more would be worse off after a 0.5 per cent rise in National Insurance takes effect in 2011, but Mr Darling retorted that the Tories had got their sums wrong and that only people earning more than £100,000 would be affected.

The increase in the personal tax-free allowance for everyone earning less than £100,000 would make up for the higher NI contributions, Mr Darling said.

Questioned on the Today programme, he accused the programme of "running the Tory line", and insisted: "You have to look at the changes across the entire tax system."

Mr Darling acknowledged that, to pay for his fiscal measures, public borrowing would balloon to £118 billion in the next financial year, way above the £38 billion he forecast in March. But he brushed aside any suggestion that the British government was saddling itself with more debt than the economy could bear.

Asked if markets could absorb the additional gilts supply caused by his expanded borrowing, he said: "I’m confident we have made the right judgement, and the government can meet all its objectives and obligations.”

The Conservatives have also complained that the House of Commons will not have an opportunity to discuss Mr Darling's fiscal stimulus package for more than a week, as Parliament is due to rise on Thursday and not return until the Queen's Speech on December 3.

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