Mandela, former South African president and former prisoner of that country's apartheid government, called for trade justice, an end to rising debts for the poorest countries, and more and higher-quality aid.


"Where poverty exists, there is not true freedom," said Mandela, who wore a white strip of cloth around his wrist. "The world is hungry for action, not words. I am proud to wear the symbol of this global cause to action."


Walking with a stick and wrapped in a black coat and brown fur hat, Mandela made an impassioned speech in front of South Africa House, for decades a symbol of apartheid.


"Massive poverty and obscene inequality are such terrible scourges of our times ... that they have to rank alongside slavery and apartheid as social evils.


"In this new century, millions of people in the world's poorest countries remain imprisoned, enslaved and in chains," he said. "They are trapped in the prison of poverty. It is time to set them free."


Britain holds the presidency of the Group of Eight nations this year, and G8 leaders have promised to focus on the issue of poverty when they meet in Scotland in July.


Mandela called on the world's leaders to honor their commitments to the world's people.