Barack Obama accused John McCain of being erratic and unsteady yesterday, intensifying an aggressive counter-attack against the assaults on his character and background that have been hurled at him in recent days by the Republican’s campaign.

Kicking off a two-day swing through the critical battleground of Ohio, where defeat for Mr McCain on November 4 would almost certainly end his White House hopes, Mr Obama lambasted his rival’s responses to the financial crisis that threatens to devastate the US economy - but which has been a boon to the Democrat’s presidential campaign.

After a week in which Mr McCain and his surrogates have attacked Mr Obama’s past connections to William Ayers, the Vietnam-era domestic terrorist, and Antoine “Tony” Rezko, the convicted Chicago financier, the Democrat fused two of Mr Mccain’s greatest vulnerabilities - his age, and the financial crisis - during a rally in Dayton.

Launching a “jobs tour” of Ohio, in a speech focused entirely on the economy, Mr Obama decried Mr McCain’s latest $300 billion plan to buy up and refinance bad mortgages as one that would “underwrite the greed and irresponsibility of Wall Street.”

He added: “His first response to this crisis in March was that homeowners shouldn’t get any help at all. Then, a few weeks ago, he put out a plan that basically ignored homeowners.

“I don’t think we can afford that kind of erratic and uncertain leadership in these uncertain times. We need steady leadership in the White House. We need a President we can trust in times of crisis.”

Mr Obama spoke as the Gallup daily tracking poll gave him his biggest national lead, 11 points, just 25 days before the election. Yet four other national polls had the Democrat only between four and six points ahead, signalling that the race is far from over and still volatile.

After a week in which two speakers at increasingly raucous McCain-Sarah Palin rallies have invoked Mr Obama’s middle name of Hussein - something their campaign later denounced - the Arizona senator, in an interview on Fox News, called his rival untruthful, “extreme” and unqualified to be President.

At a rally with Mrs Palin in Wisconsin, Mr McCain was asked by a member of the crowd about mounting allegations yesterday of widespread fraud by a liberal voter registration group. Thousands of allegedly fake registrations filed by the Association of Community Organisations for Reform Now, commonly known as ACORN, are being investigated in at least nine battleground states.

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