During the Battle of Britain and the Blitz, British newspapers regularly published official German statements about the progress of the air war. Those relating to the war over Britain could be checked against both British communiques and, to an extent, personal experience. There were large discrepancies: for example, for 7 September 1940, the Luftwaffe claimed to have lost 26 aircraft compared to 94 lost by the RAF. The British claims were almost precisely inverse: 22 British losses to 99 German.1 Partly the differences were inherent in the nature of air combat: the same kills were often claimed by different pilots, aircraft which may have looked like goners somehow made it back to base. But in the era of Dr. Goebbels and Lord Haw-Haw, there must also have been great suspicion of anything said by any German official. According to a leading article in the Manchester Guardian, what 'the German High Command [says] on the eve of or in the course of an attack, is not evidence'.2
But there was also the air war over Germany. Here, German official statements were one of the few sources of information about the effectiveness of Bomber Command's assaults on Germany available to the British press. The very same leading article noted a discrepancy here as well, a different kind. The first really big raids on London, on 7 September 1940, killed around 400 civilians and injured 1300, according to first reports. But strangely, these casualties were far greater than those being sustained in Berlin:
Our own aircraft were over Berlin for nearly three hours on the previous night [6 September 1940] and attacked an aeroplane engine works at Spandau as well as a Berlin power station. According to the official statement made in Berlin on Saturday the anti-aircraft protective was forced by the third wave of bombers and in a working-class district fires were started and "appreciable damage done to buildings." Yet the casualties are given as three people killed and several injured. It is to be concluded either that the casualty list has been incompletely compiled or else that our bombers showed even more ability at confining themselves to their legitimate objectives than they did in forcing the city's defences.3
'[I]ncompletely compiled' seems an unnecessarily polite way of calling the Germans liars, but I'll let that pass. The first thing to note is that there are several alternative explanations for the difference in reported casualties between Berlin and London that the Manchester Guardian neglected: for example, maybe Berlin's ARP was better than London (lots of deep shelters, perhaps); or maybe Bomber Command wasn't hitting Berlin as hard as the Luftwaffe was hitting London. Neither of those possibilities would have been very palatable.
The editorial conclusion is, I think, very revealing:
The apparent contrast in casualties inflicted would argue a much closer and more effective concern with legitimate targets on the part of the R.A.F.4
So, rather than discount the German claims of light casualties as more of the usual lies, designed to show the world that Germany was winning the air war, the Manchester Guardian evidently preferred to regard them as true, because that confirmed the belief that Bomber Command was only attacking legitimate (that is to say, military) objectives, unlike the Germans. In this way, German propaganda seems to have fostered the delusions of both countries.