Candles and flowers are already building up at the gates of Princess Diana's former London residence to mark 20 years since her death, which unleashed an unprecedented outpouring of grief in Britain. "She was this ray of light in a fairly grey world," Prince William said of his mother Diana, princess of Wales, whose death two decades ago on Thursday shocked the world.

"I still feel that love, I still feel that warmth 20 years on," her eldest son said in a new documentary marking the anniversary. "If I can be even a fraction of what she was, I'll be proud."The life of Diana, a shy, teenage aristocrat who suddenly became the world's most famous woman, and her tragic death at 36 still captivates millions across the globe. Two decades on, her sons William and Prince Harry only now feel able to talk publicly about her death, a seismic event which continues to resonate in the monarchy and British society.

Diana died in a car crash in Paris in the early hours of Aug. 31, 1997, along with Dodi Fayed, her wealthy Egyptian film producer boyfriend of two months, and a drink-impaired, speeding driver Henri Paul, who was trying to evade paparazzi.

The 10th anniversary of her death was marked with a memorial service and a charity concert at Wembley Stadium in London.

The passing of another decade has allowed for greater perspective, and this anniversary has been more reflective, marked by William, 35, and Harry, 32, opening up about their mother's life, and death.

No public events are planned for today, but yesterday, the brothers walked around the garden which has been especially created in her memory at Kensington Palace, her London home. They met with representatives from charities she supported.

Candles, bouquets of flowers and pictures from well-wishers are already building up at the palace gates, while hardcore Diana fans have turned up with a cake bearing her picture. But the scene is nothing like the sea of flowers laid in the week between her death and her funeral: an outpouring of national grief that commentators are still grappling with.

William and Harry have spoken of struggling to comprehend the "alien" tide of public mourning from people who did not know their mother, at a time when they, aged 15 and 12, could not process their loss. Britain, the nation of the stiff upper lip, was now wailing and hurling flowers at a hearse.

A public that had lapped up every twist and turn in the life of their fairytale princess was crying for their lost icon, killed in the chase for the next day's pictures.

Diana married Prince Charles, the heir to the throne, in 1981, but their marriage collapsed under the strains of public duty and their incompatibility. The monarchy's shining star, now a fashion icon, humanitarian and self-styled "queen of hearts," found herself cast out of the royal family in the 1996 divorce she did not want but had made inevitable with an unprecedented and explosive television interview.

With all her mistakes and frailties played out in public, Britons felt wrapped up in Diana's life.

A testament to her enduring impact, British newspapers has been filled this month with special pull-outs and magazine articles covering all facets of Diana's life.

The complexity in Diana's character still fascinates. Her strange combination of fragility and steel, her need for loving attention and an ability to make those she met feel loved. She also had a caring nature mixed with a brutal vengeful streak and the air of being an ordinary girl but was actually a blue-blood aristocrat.