British billionaire Gerald Cavendish Grosvenor, one of the world's richest people, died on Tuesday according to his estate. The 64-year-old Duke of Westminster died at a hospital in Lancashire, north-west England, a spokeswoman for his estate said. He had been taken there from his sprawling country estate Abbeystead where he had "suddenly been taken ill", she added, without giving further details of the illness. "His family are all aware and they ask for privacy and understanding at this very difficult time."