Barack Obama has opened up a significant lead over Hillary Clinton in two new polls published a day before voters go to the polls in New Hampshire.

Boosted from his clear victory in Iowa on Thursday night, Mr Obama has now has surged ahead of Mrs Clinton in New Hampshire, according to the surveys published on last night.

A USA Today/Gallup poll, conducted on Friday, has Mr Obama on 41 per cent, Mrs Clinton on 28, and John Edwards on 19. Another poll conducted by a local New Hampshire network, in conjunction with CNN, has Mr Obama 10 points ahead of Mrs Clinton. Last week, before his win in Iowa, he was six points behind Mrs Clinton in New Hampshire.

A significant number of New Hampshire voters are still undecided, according to the polls, but if Mr Obama follows his victory in Iowa with another clear win in New Hampshire on Tuesday, Mrs Clinton's White House hopes will be gravely endangered.

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The new polls were published as Mr Obama and Mrs Clinton continued their argument about who can bring change to America, an argument that Mr Obama appears to be winning. But Mrs Clinton is campaigning harder than ever in a race that is far from over.

Mrs Clinton is telling voters in campaign events across New Hampshire that they shoud elect a "doer, not a talker". She is also criticising Mr Obama - although not by name - for his voting record during his short three-year tenure in the US Senate.

In comments aimed at his grandiloquent claims that he is the man to untite America and bring a decisive break from the Clinton and Bush years, Mrs Clinton said: "You campaign in poetry, you govern in prose." She also said he was offering the US false hopes.

Mr Obama responded: "The real gamble in this election is to do the same things, with the same folks, playing the same games over and over and over again and somehow expect a different result. That is a gamble we cannot afford, that is a risk we cannot take. Not this time. Not now. It is time to turn the page."

On the Republican side, Mitt Romney put in a particularly strong performance against his rivals during a Fox News debate, after slipping behind John McCain in the past month. Both men desperately need need to win New Hampshire. Mr Romney is seeking to bounce back after his big loss to Mike Huckabee in Iowa, a state where Mr Romney had invested millions of dollars of his own fortune. Mr McCain, whose campaign fell apart in the summer, has fought back into contention but has banked all on victory in the Granite State.

The latest poll has Mr McCain opening a four-point lead over Mr McCain in New Hampshire, but last night Mr Romney put in his best debate performance of the campaign, particularly with regard to efforts to highlight his accomplishments as a successful businessman, a good message for the Republican electorate in New Hampshire where low taxes and fiscal conservatism are powerful issues.

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