Princess Diana remembered by London fans on her 50th birthday

(CBS/AP) As Prince William and the Duchess of Cambridge tour Canada, fans in London are gathering at Kensington Palace, their  soon-to-be London home,  to pay tribute to his mother, the late Princess Diana.

Pictures: Princes Diana
Pictures: Prince William and Kate in Canada

Friday, a bright sunny day in London, would have been the troubled royal's 50th birthday.

Cards, a cake, a collage and other mementoes were among the gifts left at the gates of Kensington Palace, where Diana once lived -- an echo of the massive, makeshift memorial set up there following her 1997 death in a Paris car crash.

"She would've been so popular still. Everyone would have been here to help celebrate," said Kathy Martin, a 49-year-old childcare worker from Australia. "We'll never get to see her grow old."

Martin was one of several hardcore Diana loyalists at the gates -- a testament to the hold the princess still has on many fans. They were joined by passers-by, tourists and other admirers, many of whom left cards.

Although her public image was the "People's Princess," Diana died at a time of turmoil in her life. A discreet and lengthy romance with heart surgeon Hasnat Khan had recently ended; her relationship with wealthy playboy Dodi Fayed, who died with her in the accident, was less than two months old.

Martin said it was probably because Diana died young -- at only 36 -- that she and others were still so drawn to her story.

"Marilyn Monroe was an icon, Grace Kelly was an icon,and Princess Diana was an icon," she said. "They all died young. They'll be remembered as princesses -- beautiful, radiant, princesses."

John Loughrey, a 56-year-old who attends just about every Diana-themed event, was the man behind the custom-made cake bearing her name in pink. He said Diana was "just like a magnet."

"The press followed her everywhere and the people followed her everywhere," he said. "Diana's still here in spirit."