Nelson Mandela has called on the British people to lead the campaign against global poverty.

Ahead of this weekend's meeting of G7 finance ministers, which he will personally address, the former South African president said "poverty and inequality are such terrible scourges of our time".

Addressing crowds in London's Trafalgar Square, Mandela said he could "never thank the people of Britain enough for their support in the campaign against Apartheid" during his imprisonment.

But he said that energy must now be directed towards the international campaign on trade, aid and debt.

"It is manmade and it can be overcome and eradicated by the acts of human beings," Mandela said.

"In 2005 there is a unique opportunity for making an impact," he added.

"Tomorrow, here in London, the G7 finance ministers can make a significant beginning.

"The G8 leaders, when they meet in Scotland in July, have all promised to focus on poverty, especially in Africa. I say to those leaders: Do not walk away."