The whispers focus on a young woman who in 2004 was hired to work on his team for his bid to become a senator.

The woman was purportedly sidelined from her duties after Senator Obama’s wife, Michelle, became convinced that he had developed a personal friendship with her.

The allegations were initially circulated in August, just two weeks before the convention at which Obama finally beat his opponent for the Democratic Party nomination, Hillary Clinton.

The woman, now 33, vigorously denies the vicious and unsubstantiated gossip.

And some Washington insiders suggested that she was the victim of an 11th-hour attempt to smear Obama by die-hard Hillary supporters.

But now the rumours have resurfaced, suggesting that they may be coming from elements in the Republican Party.

According to sources interviewed by The Mail on Sunday, the respected Los Angeles Times, the tabloid National Enquirer and the huge ABC television network have been provided with the woman’s name.

In the most commonly-purveyed version of the rumour, she was ‘exiled’ to a Caribbean island because Michelle Obama objected to her job on the 2004 campaign.

A lawyer representing the woman said: ‘Although her duties on the [2004] campaign changed over time, there was never any hint that Mrs Obama had any concerns about her relationship with the Senator or played any role in recommending a change in her duties.’

According to our investigation into the rumours, they originated with political veterans who claim to be loyal Democrats.

They have tried to persuade reporters that they have the woman’s interests at heart.

One of the sources who has been circulating the rumours admitted never meeting the woman but claimed he has spoken to ‘a group of African American’ women who are
her friends and believe she was mistreated.

Denial: The woman, whose identity we have protected, rejected the claims

‘They said she was removed from her position and the political scene because Michelle got wind of the fact that she had a close friendship with her husband,’ the source said. ‘She disappeared, then she reappeared in the Caribbean.’

The Mail on Sunday located the woman in the Caribbean, where she now works. She denied that Mrs Obama had raised any objections to her job on the 2004 campaign.

‘No,’ she said. ‘Nothing happened. I just left ... at the end of the campaign.’

Asked about the claim that Mrs Obama accused her of having a close friendship with the Senator, she said: ‘I have no comment on anything.

‘I switched careers. That’s it. I’m a Democrat and I support Senator Obama ... I don’t have anything to say.’

She added that she emigrated to the Caribbean from the US after falling in love with the man with whom she now lives.

Senator Obama’s team did not respond to our request for comment.

But one day after we contacted Obama’s team, a London law firm informed The Mail
on Sunday that it had been retained by the woman to help her to counter the whispering campaign, which they said was ‘absolutely false’.

In the Presidential race, polls showed that with just over three weeks to go until the November 4 election, Mr Obama is leading his Republican rival John McCain.

A Newsweek poll published on Friday showed Illinois senator Mr Obama ahead of the 72-year-old Arizona senator by 52 per cent to 41 per cent.

A month ago, that poll had the two candidates tied at 46 per cent. Other polls in the most contested states have also shown a swing toward Mr Obama. He seems to have benefited as voters anxious about turmoil on Wall Street and across the globe give him higher marks for economic leadership.

Addressing a public meeting in Ohio, Mr Obama called for a plan to help small American businesses hampered by the credit crunch to get loans for operating expenses and payrolls. He urged the world’s finance ministers to take co-ordinated action to tackle the crisis.

‘In this global economy, financial markets have no boundaries. So the current crisis demands a global response,’ he said. Pushing a line of attack that seems to have helped him build an advantage, he said Mr McCain ‘doesn’t really seem to get what’s going on’ with the financial crisis.

Mr Obama mocked a McCain adviser for telling reporters amid a week of panic-selling on Wall Street that he didn’t think it made sense for the campaign to speak daily on
the markets.

‘Senator McCain’s campaign manager actually said that Senator McCain wasn’t talking about the market because there’s just not much a candidate for president can say – and they aren’t sure what he’d say each day even if he did talk about it,’ Mr Obama said.