Tributes to Nelson Mandela at London's Westminster Abbey

Britain's Prince Harry (L) shakes hands with South African Archbishop Desmond Tutu as he arrives at Westminster Abbey in London on March 3, 2014 for a memorial service for former South African president Nelson Mandela. By John Stillwell (Pool/AFP)

London (AFP) - Two of Nelson Mandela's daughters joined Nobel laureate Desmond Tutu, British Prime Minister David Cameron and Prince Harry on Monday at a memorial service for the former South African president in London.

South Africa's deputy president, Kgalema Motlanthe, was also among about 2,000 guests invited to Westminster Abbey to celebrate the life and work of Mandela, who died in December aged 95.

In an address to the congregation, Tutu praised the anti-apartheid movement in Britain, including those who had picketed the South African embassy and helped boycott South African sport in the 1970s, such as former minister Peter Hain.

"Thank you, you who regularly picketed South Africa House, thank you elegant ladies who boycotted South African goods, thank you to all those who followed the long-haired Peter Hain to stop South African sports, thank you all those incredible young people in other parts of the world," Tutu said.

The former archbishop of Cape Town added: "What would have happened had Mandela died in prison as was the intention and hope of the upholders of apartheid?

"I suppose most would have regarded him as no better than a terrorist -- after all, persons in high positions in Britain and the US did dismiss him as such."

Prince Harry attended as a representative of his grandmother, Queen Elizabeth II, while other guests included Mandela's two daughters by his second wife Winnie, Zenani and Zindziswa, and actor Idris Elba, who played Mandela in a film last year.

Hain, whose parents fled apartheid to Britain and who later served as a minister under former prime minister Tony Blair, told guests of his "great privilege" of having known Mandela.

A permanent memorial stone for Mandela will be installed at the abbey later this year, putting him in the company of Winston Churchill, Shakespeare, Martin Luther King and Oscar Wilde.

The dean of Westminster, John Hall, said: "His remarkable constancy under suffering stands as an example to everyone.

"In addition, his capacity for forgiveness and his generosity of spirit show what humanity at its best can achieve."

London's statue of Mandela, unveiled in 2007 in his presence, stands across from the abbey in Parliament Square.