Wherever Diana, Princess of Wales (security code name "Purple Five Two") went, in public or private, she was shadowed by her Scotland Yard personal protection officer, Inspector Ken Wharfe, whose job it was it keep her safe. The SAS-trained officer from the Yard's elite Special Operations 14, Royalty and Diplomatic Protection Department, was with the Princess every step of the way. In the six years that Ken was at Diana's side they traveled hundreds of thousands of miles together, sharing secrets, laughter, and tears on a truly extraordinary journey. This is his exclusive story.