This is the story of Queen Caroline’s favourite ghostwriter, the infamous Captain Thomas Ashe, who was also an adventurer and sometime blackmailer. His unpublished novel, The Claustral Palace: or Memoirs of The Family, carried out Caroline’s threat to ‘blow the roof off the Nunnery’, revealing the secret lives and loves of the daughters of King George III in their unmarried confinement at Frogmore, the UK marital home of Harry and Meghan (for a short time). A blackmailing synopsis was circulated to members of the royal family. It was then stolen by government agents and preserved by the Treasury Solicitor. James Travers describes for the first time the significance of this novel, its author, and his relationship with Caroline, the estranged wife of George IV, and with the government of Spencer Perceval, whose untimely death the author predicted. Did Perceval himself blackmail his way to power? The novel itself is a never-before-seen gothic bodice-ripper about the royal princesses and their clandestine lovers at Frogmore, based on Caroline’s own confidences gained from Princess Elizabeth. Later encouraged by shadowy figures allied to the Irish statesman Daniel O’Connell, Captain Ashe blackmailed and threatened the life of the Duke of Cumberland and preoccupied the cabinet meetings of the Duke of Wellington.