London - Britain's Prince William has spoken of the "emptiness" he often feels about the loss of his mother, the late Princess Diana, in 1997 when he was aged just 15.

The prince, now aged 26 and second-in-line to the throne, made his unusually candid and personal remarks in an article for the Daily Mail Friday, based on a speech he gave at a children's charity co- founded by Diana.

"What my mother recognized then - and what I understand now - is that losing a close family member is one of the hardest experiences that anyone can ever endure," he wrote.

"Never being able to say the word 'Mummy' again in your life sounds like a small thing. However, for many, including me, it's now really just a word - hollow and evoking only memories."

Prince William said the feeling of loss was particularly strong on occasions like Mother's Day, which is marked in Britain on March 22.

Prince William said he had become a patron of the Charity for Bereaved Children because he understood what it was like to "lose someone you love so much."

Princess Diana, the former wife of Prince Charles, died in a car crash in Paris on August 31, 1997.