LONDON (AFP) - Prime Minister David Cameron led tributes to Nelson Mandela in a special session of Britain's parliament on Monday, hailing the anti-apartheid icon's "belief in human dignity" and ability to forgive.

British lawmakers normally reserve tributes for their own statesmen, but they packed into the House of Commons to pay their respects to South Africa's first black president, who died on Thursday aged 95.

Cameron told parliament that Mandela had shown his character "not only in the determination with which he fought, but in the grace with which he won".

"What sustained him throughout all was a belief in human dignity, that no one is naturally superior over anyone else," Cameron said.

"Nearly three decades in prison could so easily have left him bitter. On his release he could have meted out vengeance on those who had done him so much wrong. But perhaps the most remarkable chapter of Mandela's story is how he took the opposite path." Cameron said the best way Britain could honour Mandela would be to make further efforts to eradicate poverty.

"It was a long walk to freedom, but the walk is over, freedom was won - and for that Nelson Mandela has the deepest respect of this House and his enduring place in history," the prime minister said.

Cameron will be joined by all three surviving former British premiers - John Major, Tony Blair and Gordon Brown - at a massive memorial service for Mandela in Soweto on Tuesday, along with dozens of heads of state including US President Barack Obama.

The leader of the main opposition Labour party, Ed Miliband, described Mandela as "an enduring and unique symbol of courage, hope and the fight against injustice".

Parliament erupted into laughter as Miliband recalled how Mandela attended the Labour party's conference in 2000 and, with typical wit, described himself as "an unemployed pensioner with a criminal record".