William Tallon joined the royal household at 15 and, from lowly beginnings, rose quickly to become the top man: the Queen Mother's devoted servant, friend and confidante. He knew the Queen Mother longer than her own husband did, and enjoyed the royals' trust for 50 years. Tallon handled his power with perfection, seemingly untouchable. The programme explores Tallon's royal odyssey, with access to his private photographs (including off-duty pictures of the Queen Mother), notes from the Queen Mother and Princess Diana, and interviews with those who knew the real man. But despite his popularity and devotion to the royals, how did he end up alone and hounded by the press in a small Kennington flat? Did the palace officials resent his power? Were they out to get him? Billy's story is told from its humble start to his sudden death.