LONDON — President Clinton endorsed Gordon Brown as Prime Minister Blair’s successor yesterday when he praised the chancellor’s “brilliant” vision for the future.

Addressing the Labour Party conference the day after Mr. Blair’s emotional farewell to the party and country, Mr. Clinton indicated that he believed that Mr. Brown would carry forward New Labour’s reform program.

Mr. Clinton reminded Labour activists that they were losing a world-class leader and reinforced Mr. Blair’s message to the conference on Tuesday that Labour should not retreat to its “comfort zone” after he was gone

He said they should be proud of the “stunning” success that Mr. Blair had achieved as prime minister. But he said his own experience in America showed that voters did not realize that things could change quickly when power changed hands.

The former president left office in 2000 after two terms in the White House and saw his Democrat vice-president, Al Gore, defeated in the election.

He warned Labour delegates: “I think one of the biggest problems right now is that people take your achievements and your ideas for the future for granted.

“The reason is: We have produced prosperity and social progress for so long it’s easy for people to believe it’s just part of the landscape.”

Voters either thought the achievements would have happened anyway, or they believed if that if the “faces in the driving seat” changed, the new crowd would not ditch the things that worked.

Describing Labour as the agents for change in Britain, Mr. Clinton said only progressive governments could provide improvements at home and global leadership abroad.

Labour had to show that low unemployment, reduced inequality, and a strong economy were “not an accident,” he argued.

Mr. Clinton said Mr. Brown had a “brilliant vision for the future.” He praised the chancellor’s “brilliant economic leadership” and his commitment to tackling climate change and providing education for children in Africa.

Mr. Clinton, who last addressed a Labour conference four years ago, was given a standing ovation as Mr. Blair introduced him as a “superlative politician, a tremendous leader of America — the one and only Bill Clinton.” The former president said Mr. Blair’s farewell speech to the conference on Tuesday was a “magnificent valedictory. It was proud but humble, hopeful but cautionary.”

Mr. Clinton said in 1997 the British people had turned to Mr. Blair and New Labour with its unique commitment to progressive ideals.