Sefton Delmer had been the Daily Express correspondent in Berlin, had known the Nazi leadership personally, and spoke German with a fluency and vulgarity that no other British broadcaster could match.
From May 1941 he ran black propaganda for the Political Warfare Executive, and black is a technical term. White propaganda is openly attributed to its source — the BBC German service. Grey conceals the source. Black actively claims a false one, and Delmer's stations claimed to be German.
Gustav Siegfried Eins purported to be a clandestine station run by a group of patriotic German officers, disgusted not with Nazism's aims but with its corruption. Its presenter, Der Chef, was a foul-mouthed Prussian reactionary who denounced party officials as profiteers and perverts, complained that the front-line soldier was being betrayed by the swine in the rear, and delivered detailed obscenity that no British ministry could plausibly have authored — which was the point.
Soldatensender Calais, from 1943, was more sophisticated: a full-service station with excellent dance music, accurate news, and genuine service information, purporting to be a German forces station.
The technique is a ratio.
Delmer's stations carried a great deal of true, checkable, locally specific material: which streets in which cities had been bombed, which units had moved, which officials had been transferred, real casualty names read out, real football results. This came from prisoner interrogations, intercepted mail and Ultra, and it was accurate.
Into that stream went the invention: the rumor that a particular Gauleiter had a mistress and a black-market fuel supply, that a specific hospital was giving officers' families better treatment, that a particular batch of vaccines was contaminated.
Accuracy on the checkable buys acceptance of the uncheckable. That is the credibility-transfer heuristic, and it is the same mechanism as chapter 212's GARBO, applied to a population rather than to an intelligence service.
The false source does the second half. A message identified as enemy propaganda triggers resistance. The same message coded as coming from within your own group bypasses it entirely — and Hovland and Kelman's work on the sleeper effect adds that even where a source is later discounted, the message frequently persists after the discounting cue has been forgotten.
Delmer's targets were chosen with precision: privilege, corruption, and unequal sacrifice. Attacks on the regime's ideology would have consolidated the audience. Attacks on the fairness of the burden divide it, which is what the social identity literature would predict and what Delmer knew from having lived there.
Aftermath & Cross-Reference: Source Attribution Defence