During World War I, the British counterfeited three Austro-Hungarian stamps of the Crown & Kaiser designs. Postal historians differ on their usage, with the competing theories being that (1) they were printed so propaganda materials could be secretly delivered within the Austro-Hungarian Empire, or (2) they were printed for use by Entente agents operating within Austria-Hungary.
The stamps are forgeries of Austria-Hungary MiNr. 186, 188, and 226. They differ from the originals primarily in print quality, and the use of a yellower paper (MiNr. 6 & 7) or a gray underprint (MiNr. 8).