Smash hit

His nephew, Robert Kennedy Jnr, confirmed that his uncle is in Denver and has a speech prepared, an address that, if delivered, will electrify the convention's opening night.

"He is lucid, he is sharp, he seems completely unchanged by the surgery," Mr Kennedy said, as thousands of delegates, journalists and party leaders poured into Denver's Pepsi Centre for the opening gavel of the convention at 3pm (10pm GMT).

Polls show that a significant — and increasing — proportion of her supporters are refusing to back Mr Obama, who they feel has shown little respect to either Mrs Clinton or those who supported her in an unprecedented Democratic primary. By some counts she received 18 million votes in a result that was a virtual tie.

Mrs Clinton is desperately trying to quash rumours of a continued feud with the Obama campaign, knowing that her own political future will be damaged if she is blamed for wrecking the convention.

A joint statement issued today by Maggie Williams, the former Clinton campaign manager, and David Axelrod, Mr Obama’s chief strategist, said: “We understand that some in the news media are more interested in reporting the rumour of controversy than the fact of unity.

“Senator and President Clinton fully support the Obama/Biden ticket and look forward to addressing the convention and the nation on the urgency of victory this Fall. Anyone saying anything else doesn’t know what they’re talking about. Period.”

But the message has not got through to many of Mrs Clinton’s delegates. Inside a hotel suite in central Denver, behind a door with two “Hillary for President” banners, a collection of campaign groups has gathered to carry on the battle for the former First Lady.

There, surrounded by more posters and a pink pair of boxing gloves extolling Mrs Clinton’s fighting qualities, none of these supporters will vote for Mr Obama in November. Many even promise to cast their ballot for John McCain.

Seething at what they perceive as a stolen primary election and openly contemptuous of Mr Obama’s presidential credentials, their mood has hardened in recent days amid reports that he did not consider Mrs Clinton as a running-mate or even consult her on his choice.

“There’s tons of people here who are going to vote for John McCain,” said Michelle Thomas, a lifelong Democrat who volunteered for Mrs Clinton’s primary campaign.

“Some believe the only way to correct the system is to have Obama lose. Lots think he’s simply not qualified. The number one reason for this opposition is his lack of experience.”

In the Sheraton hotel, where Mrs Clinton had breakfast today with her New York delegates, Patricia Bakalian stood with her “Hillary for President” badge.

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