According to the experts at TNA, documents now shown to be forgeries supported controversial arguments central to each of Allen's books: in "Hidden Agenda", five documents now known to be forged helped justify his claim that the Duke of Windsor betrayed military secrets to Hitler; in "The Hitler/Hess Deception", thirteen forged papers supported Allen's contention that, in 1941, British intelligence used members of the Royal Family to fool the Nazis into thinking Britain was on the verge of a pro-German putsch; in "Himmler's Secret War", twenty-two counterfeit papers also underpinned the book's core claims that British intelligence played mind games with Himmler to encourage him to betray Hitler from 1943 onwards, and that ultimately they murdered the SS chief.