President Obama calls upon Americans to overcome divisions as he marks 50th anniversary of civil rights leader Martin Luther King Jr's historic 'I have a dream' speech

President salutes progress made over the past five decades. But he concedes that work still needs to be done in tackling social inequalities

Barack Obama speaks during the Let Freedom Ring ceremony on the steps of the Lincoln Memorial (Getty Images)

Taking the spot on the steps of the Lincoln Memorial where 50 years before, Martin Luther King Jnr with extraordinary oratory implored his country to live up to its ideals of equality and freedom for all, President Barack Obama today saluted the slain civil rights leader who had stirred “America's long slumbering conscience”.

Mr Obama, whose own speeches, with biblical references and cadences, owe thanks to Mr King, paid tribute to all who fought in the civil rights movement.

“Because they kept marching America changed, because they marched the civil rights law was passed, because they marched the voting rights law was signed, because they marched doors of education and opportunity swung open,” he said.

Dimmed by a soft rain, a sea of faces beneath Mr Obama and the dozens who spoke before him once more fringed the reflecting pool on the National Mall and stretched all the way to the Washington Memorial obelisk, just as they did when Mr King told the land, “I have a dream”. No feet dangled in the pool this time - police barricades stopped that - and the atmosphere was more of commemoration than renewed agitation.

President Obama faced the burden of his speech being compared with Mr King's, which, in the five decades since Dr King delivered it, has become as hallowed a text in American history as the Gettysburg Address.

“No one can match King's brilliance,” Mr Obama said as he celebrated the progress since that day 50 years ago while also conceding that work still had to be done, citing lingering inequality, troubled inner cities and stagnant wages amid growing corporate profits. Just before he spoke, church bells rang across the capital and the United States.

Earlier, thousands participated in a new march through the city dedicated, as it was in 1963, to equality and to jobs for all. Among those vehicles leading it was a replica of the bus Rosa Parks once rode when she refused to sit in the back.

Mr Obama urged America to take inspiration from Dr King to overcome the divisions of today, including partisan gridlock.

“That's where courage comes from,” he said, “when we turn not away from each other, or against each other but when we turn to face each other… with that courage we stand together.”

Taking a line from his 2008 campaign, he said: “We might not face the same dangers of 1963 but the fierce urgency of now remains.”

Older or younger, just about anyone who had filed onto the Mall agreed that Dr King's dream is not yet fully forged. William Pitt was

six-years old in 1963. Coming to hear Mr Obama on this anniversary mattered, he said, “because things have changed and a lot of things remain the same” including “the state of mind of white people in America who are still judging the rest of us by the colour of our skin not by the content of our character”.

Just as 50 years ago, activists and politicians shared the podium with celebrities and American royalty. In 1963, a contingent of Hollywood stars was led by Charlton Heston, who lent his name to civil rights before he did to gun owners' rights, and included Marlon Brando, Tony Curtis and Paul Newman. On that day, Joan Baez sang to the crowd and so did a very youthful Bob Dylan. The dazzle in the programme came from Jamie Foxx and Forest Whitaker. The music from LeAnn Rimes.

And then there was Oprah Winfrey, media mogul, TV-channel owner, actress and Obama super-pal. “Let us ask ourselves how will the dream live on in me, in you, in all of us,” she said. “We must commit ourselves to the love that binds us and connects all of us.”

It was as John Lewis - a congressman, civil rights activist and the only speaker on that day 50 years ago who is still living - was about to speak that three US Presidents were ushered onto the Memorial steps - Barack Obama, Jimmy Carter and Bill Clinton.

“We can ride anywhere we want to ride and we can stay where we want to stay, those signs that say white or coloured are gone,” Mr Lewis said. “But there are still invisible signs. The scars and stains of racism still remain deeply embedded in American society, whether it is stop-and-frisk in New York or injustice for Trayvon Martin in Florida.”

In closing, he said: “We must never give up, we must never give in.”

If in 1963 the crowds left the Mall uplifted and inspired by what they had heard, from Dr King in particular, there was surely today a more sceptical mood.

The big speech this time was not from an activist or agitator but from a President whose has had meaning for them long before today because of his status as the country's first black President. Now they have his record on civil rights and racial politics and some had expected more.

“I did, I did,” said Anthony van Buren, 52, a retired Air Force officer. He said he thought, ironically, that if progress has been halting it may in fact be because Mr Obama is black. “It's almost like a white President can be more liberal and push harder because Obama, [if] he does it they say it is because he is only representing blacks, which isn't true.”

Even anger occasionally flared. “They say Jim Crow, we say, hell, no!” a large group of young blacks and Hispanics chanted, pushing through the crowed evoking the old segregation ways of the South.

Hassan Shabazz, 47, held a sign high declaring, “Dr King would not vote for War Criminals”. Citing word of coming strikes on Syria, of drone attacks in Yemen and Pakistan and the imprisonment of Bradley Manning, he excoriated the President. “This is an Obama whitewash. Nothing he says will be followed through, he is duplicitous with the imperial elite.”

That words of Dr King reached far beyond Washington and even the shores of America and helped to inspire peaceful protest around the world was reflected in commemorations held simultaneously, including in London's Trafalgar Square as well as in countries as far apart as Japan, Switzerland, Nepal and Liberia.

The President started by praising those present for the famous speech in 1963: “They assembled here, in our nation's capital, under the shadow of the great emancipator, to offer testimony of injustice, to petition their government for redress and to awaken America's long-slumbering conscience,” Mr Obama said.

“Because they marched, city councils changed and state legislators changed and Congress changed, and yes, eventually the White House changed. Because they marched, America became more free and fair.”

He praised “those maids, those labourers, those porters, those secretaries” who helped change the US into the nation “our children now take for granted”.

“To dismiss the magnitude of this progress, to suggest, as some sometimes do, that little has changed - that dishonours the courage and the sacrifice of those who paid the price to march in those years.”

But Mr Obama added those victories “may have obscured a second goal of the march”.

“They were there seeking jobs as well as justice,” he said.

“We must remind ourselves that the measure of progress for those who marched 50 years ago was not merely how many blacks had joined the ranks of millionaires,” Mr Obama said.

“It was whether this country would admit all people who were willing to work hard, regardless of race, into the ranks of a middle-class life.

”To win that battle, to answer that call - this remains our great unfinished business.“