The former US President Bill Clinton paid tribute to Tony Blair today and congratulated the Government on its "stunning success" in running the country.
At Labour's conference, Mr Clinton said it was "no accident" that Britain had led the fight against climate change and tackled unemployment under Mr Blair's party.
And he applauded his likely successor as Prime Minister, Chancellor Gordon Brown, for his "brilliant economic leadership".
Mr Clinton, who last addressed a Labour conference four years ago, was given a standing ovation as he stood to speak.
Introducing the former president and close personal friend, Mr Blair hailed him as a "superlative politician, a tremendous leader of America - the one and only Bill Clinton".
Mr Clinton said in 1997 the British people had turned to Mr Blair and New Labour with its unique commitment to progressive ideals.
It was too easy when times were good to forget the hard work done behind the scenes. But by any standard "your Prime Minister, your Government, your party have been a stunning success".
He told delegates: "Well done. You should be happy and you should be proud.
"I want to say a special thank you publicly to my friend Tony Blair for his leadership - his preservation of our old Atlantic alliance through quite a lot of storm as well as occasional sunshine.
"I want to thank him for his personal friendship to me - through storm and sunshine.
"I want to thank Cherie and their children for their many kindnesses to Hilary and me and Chelsea and enduring the rigours of public life.
"I want to thank Gordon Brown for his brilliant economic leadership and the entire New Labour team for their support."
Mr Clinton said the Labour Party should not be disheartened by calls for change from the electorate.
"Make no mistake about it, the question for New Labour and the British people is not whether you will change. It's how you will change and in what direction."
In an apparent swipe at the prospect of a resurgent Conservative party he added: "Do not let anyone ever present to your citizens any future choice - as long as you are debating issues in the Parliament and when the time that comes you must debate issues in the election - as change versus more of the same.
"You are the change agents in this great nation. You have been and you will be."
Mr Clinton said that in the Chancellor's speech this week he had "seen Gordon's brilliant vision of the future".
"And yesterday I heard the Prime Minister's magnificent valedictory. It was proud but humble, hopeful but cautionary.
"The most important thing to me as somebody who has been there was it was appreciative, full of gratitude, devotion and love."
He went on to say the relationship between the UK and the US is as "trade dependent" today as 100 years ago, "but the world has never been so interdependent now because our relationships go so far beyond economics.
"It's a different world. This world has been a really good deal for many of us. It's given us a chance to get a good education, to know people from different cultures, to do different things, to find out things in an instant over the internet.
"But fundamentally the fact remains that the modern world is unequal, unstable and unsustainable."
He pointed to the presence of climate change, terrorism, and the "slaughter of innocents in Darfur".
"Since we can't kill, jail or occupy all of our enemies... we also have to spend some time and money making more and more partners and fewer enemies.
"It is so much cheaper to alleviate poverty, put kids in school, fight disease, build government capacity and economic capacity in a poor country than it is to fight a war.
"You should press ahead and explain it to people in just those terms."
And he had a similar message in encouraging activists to promote the Government's work in doubling aid for Africa in leading the G8 last year.
"You should not only stand firm for it but make sure it's a voting issue where you live, because it will affect people in every village in the United Kingdom, I don't care how small."
And Mr Clinton also praised the Blair Government for signing up to the Kyoto agreements on tackling climate change, adding: "We need you to lead the rest of the world".
Mr Clinton said only progressive governments could provide improvements at home and global leadership abroad.
"You have to believe in equal opportunity and empowerment, rather than the concentration of wealth and power."
He urged delegates to remember how hard it was to stay on the "cutting edge of change" when Labour came to power and stressed how important it was that they "still be seen as agents of change" in future.
"I believe that the third way offers by far the best promise of a 21st century world of peace and security, economic progress and more just societies."
Mr Clinton recalled the day scientists discovered every single "living soul on this planet is 99.9% the same genetically".
The promise of progressive politics was "that we really do believe that our common humanity is more important than our interesting differences.
"We know that half a world away, trapped in poverty, there's some little kid ... who's just as smart as our kid and just as deserving of a decent life."
He closed by urging delegates: "Be of good cheer, take a deep breath, be proud of what you have done and go back to work.
"Stay in the future business and the people will get it."
Leaving the conference centre with Mr Blair after his speech, Mr Clinton was giving no clues on who he would like to see as the next Labour leader.
Asked by waiting reporters who he wanted to succeed Mr Blair, Mr Clinton said: "As long as the party is the party of positive change it will do fine. Stay in the future!"
However, he made clear he was not backing away from his previous comment that Gordon Brown would make a good Prime Minister, telling reporters: "I stand by what I said."
Mr Clinton was asked whether he would miss Mr Blair after he quits as Prime Minister.
He joked: "Well, I hope I'm going to see him more. If I didn't see him, I would miss him."
And the former US President quipped that he would miss Mr Blair's annual addresses to the Labour conference, as he would no longer be able to rely on them to tell him what he should be saying.Reuse content