Prince William has recalled how his late mother Princess Diana's charity work on behalf of the homeless had an impact on him as a child.The Duke of Cambridge spent time on the streets of London recently selling copies of The Big Issue and published a new essay in the homelessness charity magazine on Monday. "I was 11 when I first visited a homeless shelter with my mother, who in her own inimitable style was determined to shine a light on an overlooked, misunderstood problem," he wrote. "In the 30-odd years since, I've seen countless projects in this space grow from strength to strength, including charities of which I have had the honour of being Patron." Diana, who died following a car crash in Paris, France in 1997, brought William and his brother Prince Harry to homeless shelters as children, and William has become an important patron for ones including The Passage in London. He added that he now wanted to ensure his concern for homelessness is passed on to his children Prince George, eight, Princess Charlotte, seven, and four-year-old Prince Louis. "In the years ahead, I hope to bring George, Charlotte and Louis to see the fantastic organisations doing inspiring work to support those most in need – just as my mother did for me," William added. "As she instinctively knew, and as I continue to try and highlight, the first step to fixing a problem is for everyone to see it for what it truly is." Praising the royal, The Big Issue co-founder John Bird said: "The scale of interest in William selling The Big Issue has been enormous. And it puts our vendors and their sterling work in the public eye again. Anyone can sell The Big Issue, even a Prince!" Prince William turned 40 on Tuesday.