A widespread assumption in 1913 was that the mysterious airships then being seen in British skies were real and German. The vast majority certainly were not: there were just too many of them, in too many places, for no conceivable purpose. But it remains a possibility that a few of them really were German airships. In particular, competent authorities then and later have concluded that the Sheerness incident on 14 October 1912 was caused by the intrusion of a Zeppelin into British airspace. At a meeting of the Committee of Imperial Defence in December, Winston Churchill, the First Lord of the Admiralty, reported that
There was little very doubt that the airship reported recently to have passed over Sheerness was a German vessel, and this incident had renewed anxiety. 1
At the next CID meeting, in February 1913, Vice-Admiral Sir John Jellicoe stated that 'A German airship of the Parseval type had flown over Sheerness and back to Germany'.2 When the Prime Minister, H. H. Asquith, asked what the evidence for this was, Jellicoe replied that 'it was known that an airship had left Germany on the day previous', and Churchill added that there was 'information from other sources which confirmed their belief'.3 The nature of these 'other sources' is suggested by a letter written by Churchill to Admiral of the Fleet Sir A. K. Wilson several days earlier, though then the implication was not that it was a Parseval but rather Hansa, a civilian Zeppelin:
14. Visit of 'Hansa' over Sheerness.
One of the pilots of the Bristol and Colonial Aeroplane Company, Mr. E. Harrison, recently visited Farnborough, and stated that he was in Germany on the night of 13th October, and saw the 'Hansa' start on a trip, and he stated that everybody knew that she had been over the North Sea. The 'Hansa' is an older and smaller airship than the German naval airship.
It has not been thought advisable to take the matter up closely with Mr. E. Harrison, but enquiries are being made in other directions to confirm the accuracy of this information.4
I'm not aware of the results of these further inquiries. But in 1931, C. F. Snowden Gamble, an early aviation historian, perhaps drew on Admiralty sources for his flat assertion that Hansa did indeed fly over Britain (though without specifically mentioning Sheerness):
There is every reason to believe that, at the time, the Admiralty knew that the craft was the Hansa -- a Zeppelin airship belonging to the Deutsche Luftschiffahrt A.G. (German Airship Transport Company) but manned by naval officers and ratings. Although the allegations were denied by the German press there is now no doubt that this ship did cruise over part of southern England.5
John Cuneo remarks that Gamble's confidence is hard to understand, 'because the facts are far from being well-known despite the insinuation by the author. No reference is given although the history is otherwise unusually well documented'.6 He attempted to find supporting evidence in published sources, including the Official History and Flight, but was largely unsuccessful.7
No date is given of the cruise or cruises of the Hansa but it seems to place it over England in 1912 or the early part of 1913. It is true that this Zeppelin was used to train navy crews and such training frequently took place over the North Sea but this was only after the explosion of the only naval airship in October, 1913. Of course a special trip was a possibility. It seems peculiar that such a visit was not described by some Zeppelin commander or crew member in the flood of post-war revelations.8
For that matter, it also seems peculiar that no archival records of such a flight have ever turned up. Douglas Robinson, who drew on the logbooks of the Naval Airship Division and other sources, dismisses the phantom airship reports as 'alarmist rumours' and likens them to 'the "flying saucer" craze of our own day'.9 Of course, he might have missed something, or the records might not have survived. Or the crew might not have survived the war to write their memoirs. It would certainly be unwise to dismiss altogether the possibility that evidence from German primary sources might turn up: after all, the contemporary spy scare was ridiculed then and later, but there were some German spies in Britain before the war, just not remotely as many as was claimed.10 In fact, one of those spies published a book in which he claimed that a German airship secretly flew over London in peacetime. Was he telling the truth? I'll leave that for another post.