According to Lars Moen, author of 'Under the Iron Heel', 1941, he witnessed the German Invasion fleet exercising off Antwerp in September, 1940, and later, in October he mentions a number of dead German soldiers being washed ashore, and many wounded in the hospitals there. He surmised that it was a failed attempt at the invasion of Britain, but in my opinion, it was an exercise off the Belgian coast that went wrong.
British grey propaganda?
From 'Black Propaganda in the Second World War' by Stanley Newcourt-Nowodworski, 2005. Page 112.
A sib is a wartime British propaganda rumour."On the other hand , a short sib put out at about the same time became one of the most successful of the whole war: 'The English have invented a method of setting the sea on fire.' It was disseminated using several channels and soon there were eyewitness reports of charred bodies, the casualties of an unsuccessful invasion. According to Wehrmacht barrack-room gossip, hospitals equipped to deal with burns were being set up all along the Channel coast. What is more, the German navy started to test fireproofed invasion craft and asbestos suits for their crews. The story stuck. As late as Christmas 1944 (I was then working for the gardener in the Rhineland) I heard from a young Waffen-SS man that, according to a veteran in his unit, a trial Operation Seelowe was repulsed by the dastardly British who had set the Channel on fire."
White propaganda. An open activity where the originator does not hide or disguise his identity, he speaks for his government.
Black propaganda. Hides its origin behind false signatures, and usually purports to be produced by clandestine organisations within the enemy country.
Grey propaganda. Anonymous, it bears no signature and leaves the target guessing its origin.