Gordon Brown has been accused by a senior Tory of deliberately pushing the UK into "as much debt as possible" in an effort to make life tough for any incoming Tory government.
William Hague, de facto deputy to party leader David Cameron, compared the Prime Minister and his Labour administration to a retreating army "poisoning the wells".
In a dramatic escalation of pre-election skirmishes over the economy, the shadow foreign secretary launched a serious attack on the PM in an interview with the News of the World.
"They are like a retreating army, poisoning the wells as the other army advances," the former party leader told the newspaper.
"That is precisely what Gordon Brown is doing by chalking up as much debt as possible, making as many spending commitments as possible which he doesn't know how to finance, partly in the hope of leaving a new government with a really difficult situation. To say we will inherit a poisoned chalice if we win the general election is putting it mildly. It's as poisoned as it can get.
"Gordon Brown's troops are leaving as much poison as they can. It is almost as if they have given up caring."
Mr Hague spoke out after official records this week showed the public sector borrowed in January for the first time on record.
Net borrowing was £4.3 billion in a month which usually sees a seasonal surplus thanks to income and corporation tax, according to the Office for National Statistics (ONS).
For the 10 months of the financial year so far, public sector net borrowing has reached £122.4 billion with the UK's net debt now £848.5 billion, which is equivalent to 59.9% of the country's annual output - the highest proportion for a January since the 1974 financial year.
Chief Secretary to the Treasury Liam Byrne said: "It's very sad that Mr Hague is stooping this low. Because we took the action we did, unemployment, bankruptcies and repossessions are far lower than people saw in the '90s. That's not poisoning a well; it's called protecting our country."
