LONDON, Dec 6 — Britain's Prince William called yesterday's death of Nelson Mandela “extremely sad and tragic”, immediately after attending the London premiere of a film celebrating the life of the iconic anti-apartheid fighter.

Mandela's daughter Zindzi was also at the screening of “Mandela: Long Walk to Freedom”, insisting on her way into the cinema in London's Leicester Square that her father was “fine” but “frail”, and that she was “hoping to see more of him.”

It is not known where she was when she heard about her father's death, but British news reports suggested she “seemed to be overcome” once inside.

William was told of Mandela's death during the screening, and gave a brief statement as he left the cinema following a two-minute silence held at the end of the film.

“We were just reminded of what an extraordinary and inspiring man Nelson Mandela was and my thoughts and prayers are with him and his family right now,” he said, flanked by his wife Catherine.

It is believed to be the first time a major royal has given an unscripted response to a large news event.

British Prime Minister David Cameron said “a great light had gone out” as flags flew at half-mast at his Downing Street Office.

“Nelson Mandela was a towering figure in our time; a legend in life and now in death — a true global hero,” said Cameron.

“Across the country he loved they will be mourning a man who was the embodiment of grace,” he added.

“Meeting him was one of the great honours of my life. My heart goes out to his family — and to all in South Africa and around the world whose lives were changed through his courage.

“A great light has gone out in the world.”

Opposition leader Ed Miliband said the world “had lost the global hero of our age”.

“Nelson Mandela showed us the true meaning of courage, hope, and reconciliation,” he stressed.

“From campaigner to prisoner to president to global hero, Nelson Mandela will always be remembered for his dignity, integrity and his values of equality and justice.

“He moved the world and the world will miss him deeply.”

London mayor Boris Johnson praised Mandela's power of forgiveness.

“Londoners, brought up in a city where the values of diversity and equality were celebrated not suppressed, forged a unique bond with Mandela and the struggle he embodied,” he said.

“He was without doubt the pre-eminent statesman of his age. No statesman in history can match him for resilience, for grace, and for forgiveness.

“A great heart is stilled.”

Former prime minister Tony Blair said Mandela had made racism “not just immoral but stupid”.

“He was a wonderful man to be around, with a sharp wit, extraordinary political savvy and a lovely way of charming everyone in a building,” recalled Blair.

“Through his dignity, grace and the quality of his forgiveness, he made racism everywhere not just immoral but stupid; something not only to be disagreed with, but to be despised. In its place he put the inalienable right of all humankind to be free and to be equal,” he added.

Archbishop of Canterbury Justin Welby, head of the world's Anglicans, mourned the loss of South Africa's “greatest citizen and its father.”

“Nelson Mandela, fighting to the end, is freed to be with his God in joy and reward for his great service and sacrifice.

“We pray for his family, for his friends and for his country,” added the archbishop.

Irish Prime Minister Enda Kenny paid tribute to the “gift” of Mandela, and offered the country's deepest sympathies to the people of South Africa.

“The name Mandela stirred our conscience and our hearts. It became synonymous with the pursuit of dignity and freedom across the globe,” he said in a statement.

Scotland First Minister Alex Salmond said the world has lost a “towering statesman and outstanding political leader.” — AFP