Barack Obama has made history by becoming the first black American to be officially nominated as a presidential candidate.

Mr Obama made his first appearance at the Democratic National Convention in Denver to accept the nomination telling cheering delegates: "I think the convention has gone pretty well so far. What do you think?"

And in a rip-roaring speech, Bill Clinton, the last Democrat to be elected US President, described Mr Obama as "the man" to follow in his footsteps.

Mr Clinton said the often bitter primary battle between his wife Hillary and Mr Obama for the Democratic Party's presidential nomination "created so much heat it increased global warming".

But he claimed that the contest had strengthened Mr Obama's candidacy.

In a prime-time speech Mr Clinton said: "The American dream is under siege at home and America's leadership in the world has been weakened.

"Everything I learned in my eight years as president, and in the work I have done since in America and across the globe, has convinced me that Barack Obama is the man for this job."

"Barack Obama is ready to lead America and to restore American leadership in the world."

Mr Clinton said Republicans had called him "too young and too inexperienced to be commander in chief" when he ran for the presidency aged 45 in 1992 - the same criticisms which Republicans have used against Mr Obama.

"Barack Obama will lead us away from the division and fear of the last eight years, back to unity and hope," he added.

© Independent Television News Limited 2008. All rights reserved.