Brown's credit rating plunges

One of the many pertinent questions asked by the redoubtable Mrs Duffy, and which was treated with typical contempt by Labour's leader, was: "How are you going to get us out of all this debt, Gordon?"

The best that the Prime Minister could offer was a repeat four-year plan to halve the deficit, even though most respected economic forecasters believe Labour is wrong to defer the implementation of this policy until 2011.

Yet, judging by the economic "contagion" spreading across Europe, the next government – of whatever make-up – may be compelled to act far more swiftly, and savagely, than they had envisaged.

For, while Britain prepares to go to polls, Europe edges ever nearer to financial meltdown – and Britain's long-standing decision to exempt itself from the euro will offer no insurance against the fallout.

One only has to recall the UK's humiliating exit from the ERM, in 1992, the nadir of John Major's government, or the collapse of Lehman Brothers in America – Britain found itself powerless.

Mr Brown can also not hide away from the allegation that this country's plight is comparable to Greece's financial freefall.

The UK has comparable levels of indebtedness – and, as Mrs Duffy implied, the PM can no longer be trusted. As well as saddling Britain with a record debt burden, every economic prediction made by his Government has been found to be wildly optimistic.

That is why Mr Brown was treated with derision when he toured a welding machinery factory ahead of last night's pivotal debate between the party leaders.

When he remarked to Jayne Shinwell, a contract development worker, that the firm was doing well in China, the mother of two responded: "Our company's doing well everywhere, but I think it's in spite of you."

Her remarks encapsulate Mr Brown's problems – he has lost all

credibility because of his failure to be candid with voters about the scale of the economic problems domestically, and across Europe, as more and more respected forecasters warn of bleak times ahead.