The economic crisis in America appears to be giving Barack Obama a significant boost in his presidential race against John McCain, with a series of polls yesterday showing growing support for the Democrat.

One survey released last night showed women flocking to the Illinois senator, with Mr McCain losing female voters at a faster rate than Sarah Palin, his running-mate, attracted them after her extraordinary entry into the race nearly five weeks ago.

Mr Obama’s aides concede that the broad movement of the polls shows a clear shift of momentum in his favour. However, they rightly caution that the White House battle is still relatively close, polls are fickle and that, with five weeks remaining, an external event could still change the course of the race.

A Quinnipiac University survey in three battleground states — Florida, Ohio and Pennsylvania — showed a shift to Mr Obama in each of them. In Florida, where the Democrat trailed Mr McCain last month, he leads by 51 per cent to 43. In Ohio, a must-win state for Mr McCain, the Republican now trails 42 per cent to Mr Obama’s 50. In Pennsylvania the Democrat leads by 52 per cent to 39.

According to a Time survey, women support Mr Obama over Mr McCain by 55 per cent to 38. There is also a perception among voters that Mr Obama had passed the “presidential threshold” test in his first debate with Mr McCain last week. Two new national polls also had Mr Obama ahead. The Pew Research Centre gave him a seven-point lead while a Washington Post/ABC News survey gave him a lead of only four points.

Bill Clinton finally appeared on Mr Obama’s behalf in Florida at his first big rally for the Democratic candidate. “Obama’s answers are better,” he said.

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