In Dorril, Stephen, MI6: Fifty Years of Special Operations, London, 2001:
In the 1940s, while the Fourth Empire itself was spreading its tentacles across the globe, its architects came up with the clever device of raising the alarm over an alleged “Fourth Reich” (German Fourth Empire) in South America. Although the story was revived by the media and the intelligence services in the 60s and 90s, it was, of course, totally unfounded and turned out to have originated with the Establishment mouthpiece Daily Express (Dorril, pp. 96-7).
Check on twitter how many COAs & UIs are still promoting this lie. They even have a hashtag created for it: #FourthReich.
I know Ernie, you know: