Watch the Barack Obama advert | Sketch - a mawkish weepathon

Bill Clinton last night symbolically passed the baton to Barack Obama as he campaigned alongside the Democratic nominee for the first time and declared he "represents America's future".

The former president had fought hard to stop Mr Obama winning the Democratic primary this year and it took him fully 115 days after its conclusion before finally sharing a platform with the man who vanquished his wife, Hillary.

But, in front of a vast midnight rally in central Florida with less than a week to go before polling day, Mr Clinton delivered a generous - if slightly unemotional - endorsement. "I'm honoured to voice my support for Barack Obama as president," he said.

"Our country is hanging in the balance. And we have so much promise and so much peril. This man should be our president - all of our presidents - and this man will be our president unless the American people forget what this election is about."

In the primary campaign he had dismissed Mr Obama's position on Iraq as a "fairy tale" and warned voters not to "roll the dice" by picking an untested president.

Last night, however, he presented a methodical case for backing Mr Obama. His wife's erstwhile rival had the better philosophy and the best policies, Mr Clinton said, before defending him against John McCain's charges that he favoured a re-distribution of wealth that smacked of socialism.

Praising the judgement Mr Obama had shown in responding to the economic crisis, he disclosed that the Democratic nominee had consulted both him and Mrs Clinton. "You know why? Because he knew it was complicated and before he said anything he wanted to understand...The way he handled this crisis showed he will be a very, very fine decision maker."

Mr Clinton went on to suggest that the extraordinary campaign Mr Obama had run - "something nobody else could have ever done" - also showed he could execute decisions as America's chief executive.

For his part, Mr Obama said: "In case all of you had forgot, this is what it's like to have a great president." He expressed pride in being able to call both Clintons his friends - "I know how much we will need them in the months and years to come" - and paid tribute to the last Democratic administration which he had criticised during the primary campaign.

The late night rally capped another day dominated by Mr Obama which included three rallies across North Carolina and Florida, an interview with the "Daily Show," a popular comedy programme, and a 30-minute commercial aired across most of the broadcast networks.

The production fused biography and policy with the real life stories of families in key battleground states, Mr Obama became the first presidential candidate since the Texas billionaire Ross Perot in 1988 to lavish funds on a prime time effort to sway voters.

The “infomercial” blended views of Mr Obama speaking in a setting that resembled the Oval Office, glowing testimonials of the Democratic presidential candidate by politicians and business executives, and segments devoted to his upbringing by his white mother and grandparents. Even five days before the election, his aides concede that many Americans are still ignorant - and often suspicious - about his formative years.

"I will not be a perfect president," Mr Obama said, reprising a theme he has used on the stump for many months. "But I can promise you this — I will always tell you what I think and where I stand." In the half-hour film he never mentioned President Bush or Mr McCain, but sought instead to focus on his biography and plans for his presidency.

The production, which aired on seven channels at a cost of up to $5 million, included footage shot by Davis Guggenheim, the son of Robert F Kennedy’s campaign documentarian and producer of Al Gore's global warming documentary "An Inconvenient Truth”.

The film was denounced by the McCain campaign as grandiose and excessive. The Republican derided the event as a "gauzy, feel-good commercial," paid for with broken promises. Yet it also spoke to the huge financial advantage Mr Obama has over his Republican rival as the race enters its final days. Mr McCain is having to spend wisely and with some precision in battleground states, while Mr Obama has the luxury of saturating the airwaves.

"America, the time for change has come," Mr Obama said in the final moments, as the commercial cut to him speaking live from a rally in Florida. "In six days we can choose an economy that rewards work and creates jobs and fuels prosperity starting with the middle class.”

In the broadcast, the candidate was shown addressing large crowds on issues including health care, education and jobs, interspersed with the story of struggling American families, and interviews with Mr Obama's family and colleagues.

He talked about how his mother died young of cancer. "I know what it's like to see a loved one suffer, not just because they are sick, but because of a broken health care system." He pledged to protect the US while seeking to wind down the war in Iraq.

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