Gordon Brown marked 80 years since Martin Luther King's birth by insisting the rise of Barack Obama was part of his legacy.
The Prime Minister said the "true greatness" of the civil rights leader - who was assassinated in 1968 - lay in the fact that he was still giving people "the courage to dream".
Mr Brown said in a statement on the Downing Street website: "Great change only occurs when leaders inspire others to follow. When they stand up for justice and pass its torch along, person to person, to build a movement, first hundreds, then thousands and then finally millions strong.
"That is how we should honour Martin Luther King on this, the 80th anniversary of his birth and the eve of President Obama's historic inauguration.
"He was a great individual in his lifetime, but his true greatness is that even now he inspires us to believe that what others call impossible is within the grasp of those with the courage to dream."