David Cameron has seized on the escalating credit crisis to accuse Gordon Brown of failing to rein in public and private borrowing over the past decade.
In the first signs of a political fallout from the current turmoil, the Tory leader said the Government's appeal for banks to lend responsibly had come too late last week.
"This Government has presided over a huge expansion of public and private debt without showing awareness of the risks involved," Mr Cameron writes in the Sunday Telegraph.
"Though the current crisis may have had its trigger in the United States, over the past decade the gun has been loaded at home.
"Under Labour our economic growth has been built on a mountain of debt. And as any family with debts knows, higher debt makes us more vulnerable to the unexpected."
Mr Cameron said the level of personal debt had trebled in the last decade to £1.3 trillion - more than the UK's entire national income.
The result was an increasing impact on homeowners every time interest rates go up, growing numbers of insolvencies and - with Labour's "stealth tax" rises - a fall in real-terms take-home pay for the average family.
"Meanwhile, for all its past talk of prudence, the Government has been on a spending and borrowing spree of gigantic proportions," Mr Cameron goes on.
"Even despite the world economic boom, Gordon Brown is borrowing £35 billion a year - more than the entire schools budget.
"There's no wonder that the International Monetary Fund has said that this level of borrowing cannot continue: our Government is borrowing more than any other in Europe. It takes quite something to make Italy's borrowing look prudent."