A raft of new polls ahead of tomorrow’s historic presidential election show Barack Obama cementing his lead over John McCain – except for one survey that showed the Arizona senator narrowing the gap on his Democratic rival.

In a WSJ/NBC poll, conducted over the weekend, the Republican nominee has shaved two points off Mr Obama’s lead in the past week, but is still trailing by eight points, 51 to 43 per cent among likely voters.

Undecided voters accounting for 6 per cent of the electorate could still afford Mr McCain an opening, although a third of those said they were leaning towards a third-party candidate such as Libertarian Bob Barr or Green/Independent Ralph Nader. The poll’s margin of error was 3.1 percentage points.

Putting the data in context, pundits noted that the same poll in 2004 had shown Democrat John Kerry with a one-point lead over President Bush, who then went on to win the popular vote by 3 percentage points. If tomorrow’s vote follows a similar pattern, Mr Obama will score a respectable four-point victory nationally.

"The poll shows some slight movement for McCain. But with just 48 hours left, it's going to be a challenge to make up the rest of the difference," said Neil Newhouse, a Republican pollster who conducts the survey with Democrat Peter D. Hart.

"This poll has all the earmarkings of an electorate that has reached an opinion that Barack Obama would be a good president," Mr Hart said. "The uncertainties [about Senat. Obama] that were so prevalent early in the year have just melted away."

There was worse news for Mr McCain from a number of other polls released today, which showed the Illinois senator tightening his grip on the electorate as the vote approaches.

Mr Obama led by 13 points, 53 to 40 per cent, in Gallup’s daily tracking poll of registered voters, up from 11 points on Saturday and Sunday and 7 points a week ago. Among likely voters, Gallup showed him with a slightly narrower 53 to 42 per cent lead, up from 51 to 43 per cent yesterday.

A Zogby daily tracker also shows Mr Obama on an upward swing but with a narrower edge, now leading his Republican opponent 50.9 to 43.8 per cent. This represents a 1.4 point increase in support for Mr Obama since Saturday.

The Democrat’s favourable position was confirmed by a Washington Post/ABC tracking poll which gives him an 11-point margin, at the top end of the 7 to 11 point range he has commanded since the final presidential debate in mid-October.

Beneath the headline figures, the survey finds that Mr Obama has firmly reestablished his advantage on the economy, survived recent Republican efforts to brand him as a socialist and maintains a lead in perceptions of which candidate could better handle a major crisis.

The McCain campaign has been loudly dismissing such findings, noting that the path to the White House runs through the battleground states, where it claims the Arizona senator is rapidly making up ground.

In the six states the Washington Post calls "up for grabs" - Florida, Ohio, North Carolina, Montana, Missouri and Indiana - the campaign is pushing hard, with more than a third of voters there saying they have heard from the McCain campaign in the past week. That is a sharp rise from the third week of October and roughly equal to numbers who have been contacted by Mr Obama's campaign.

The Washington Post found the two candidates roughly splitting the vote in the six states combined, with 51 percent backing Mr Obama and 47 percent supporting Mr McCain.

In the Real Clear Politics poll of polls, Mr Obama has four point leads in both Florida and Ohio and a negligible 0.3 point edge in North Carolina. In Montana, Missouri and Indiana Mr McCain leads by 3.8, 0.7 and 0.5 points respectively. In Pennsylvania, where Mr McCain has been campaigning hard in recent days in hope of snatching a key victory, Mr Obama has a healthy 7.3-point advantage.

Daily tracking organisations will keep polling throughout Monday night, with the final results released on Tuesday morning.

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