In contrast to William Le Queux’s pre-1914 novels about German spies and invasion, his wartime writing is much less well known. Analysis of a number of his works, predominantly non-fictional, written between 1914 and 1918 shows that he modified his perception of the threat posed by Germany in two ways. Firstly, because of the lack of a German naval invasion, he began to emphasise the more plausible danger of aerial attack. Secondly, because of the incompetent handling of the British war effort, he began to believe that an ‘Invisible Hand’ was responsible, consisting primarily of naturalised Germans. Switching form from fiction to non-fiction made his writing more persuasive, but he was not able to sustain this and he ended the war with less influence than he began it.