Chancellor Gordon Brown outlined his vision of a "great British society" free of poverty and inequality Monday in a wide-ranging speech seen here as a coming out for his long-delayed ambitions to succeed Tony Blair as prime minister.

"It was not pessimists and reactionaries who built Britain's greatness, but visionaries, optimists and idealists," Brown said, addressing members of the ruling Labor Party at an annual conference in the seaside city of Brighton, and Britons across the country in a speech carried live on national television.

While Blair's address on Tuesday is officially the central event of the party's annual meeting, Brown's speech was perhaps as eagerly awaited. After eight years in office and a narrow victory in elections in May, Blair has announced that this, his third term, will be his last. Political analysts here endlessly debate exactly when Blair might step down, but there is near-unanimous agreement that Brown, who serves as his chancellor of the exchequer, or finance minister, will succeed him.

Clearly addressing critics who have said he would steer Britain to the political left, Brown praised Blair and echoed many of his centrist themes. "We will not just inhabit the center ground but dominate it," he said, in a speech that ranged from pensions to alternative energy but barely mentioned the Iraq war, which has severely damaged the popularity of Blair and Labor. Polls show the war is supported by about a third of the British public.

Blair, 52, and Brown, 54, rose together through the ranks of the Labor Party during years when it was in disarray and the Conservative Party held a grip on power. They have largely been credited with creating the centrist "New Labor" movement that brought the party back to power in 1997 and keeping it there since.

Alternatively described as friends and rivals, Blair and Brown have had mercurial relations for many years as Brown has waited in the wings -- at times more patiently than others -- for Blair to step aside. Analysts said that moment now appears closer at hand than ever, with increasing numbers calling Blair a lame duck.

"His message was, 'Tony Blair has done well, but I would take you further,' " said Peter Riddell, a columnist for the Times of London newspaper. "He was almost saying, 'I am going to be your next leader,' and he was trying to define the values he stands for and where he wants to take the party."

Riddell said cabinet ministers at the Brighton conference have told him they believe Blair would not step aside for at least another year or two. Blair has said he intends to serve his full five-year term. But on the eve of the conference, several key Blair aides were openly discussing how Brown was Blair's obvious successor.

In his 35-minute speech Monday, Brown, with a boxer's square face and a preacher's stern oratory, sounded like a man already on the stump. Calling for a "renewal of New Labor," a clear reference to the party's post-Blair future, Brown said he intended to make the party "the voice of the mainstream majority" and spend the next year visiting "every region" in Britain to "listen, hear and learn."

His brow dampening with sweat, he touched on topics that a finance minister normally addresses, defending the government's economic reforms, warning against protectionism and anti-European economic policies.

His speech also contained a broad political blueprint for Britain to increase anti-poverty aid for Africa and build more homes and expand public education in Britain. He called for a continued fight against terrorism, and a society in which "for every right there is a responsibility."