WILLIAM: Charles' popular eldest son is now heir apparent, and his modern and socially-conscious outlook - a legacy of his mother Diana - is seen to represent the family's future. The Duke of Cambridge is a vocal campaigner for environmental issues, and is credited with bringing a more relaxed and personal approach to royal duties and hands-on philosophy to raising children. But he has endured the breakdown of his relationship with brother Harry, with whom he was previously extremely close, since the younger sibling married Meghan Markle and left frontline royal duties.