By October 1916 the German Navy’s Zeppelin campaign against London had been decisively defeated, and the citizens of the metropolis slept undisturbed in their beds for about eight months thereafter. In the following May, however, the calm was rudely shattered when the German Army, taking over the strategic role from the Navy, sent, in broad daylight, a squadron of Gotha heavy bombing aeroplanes against south-eastern England. The intended primary target for most of the eight daytime raids carried out between May and August was, of course, the capital itself, but coastal towns also received attention. Although relatively few Gothas took part in these missions, twenty-eight being the highest figure ever achieved, this shoe-string project had, none the less, very grandiose aims; the German High Command expected it to yield substantial strategic and propagandistic benefits whereby the British nation would be intimidated into demanding peace negotiations.
The insolent day-raiders caught the Lloyd George Government completely off guard – the air defences, built up at great cost during the Zeppelin campaign, had been allowed to run down to a dangerous extent because of urgent demands for replacements for overseas commands, and supply difficulties caused by the Admiralty’s intransigence over service aviation. Indeed, all that the Home Defence Group of the Royal Flying Corps (RFC) had to send up against the well-defended bombing formations were some obsolete night-fighting aeroplanes which, although ideal against the conventional Zeppelins at modest altitudes, were virtually useless against the higher-flying Gothas – a fact that must have been known to the German air intelligence service prior to the raids. Furthermore, in the absence of effective unity of command, the responses from home-based RFC and Royal Naval Air Service (RNAS) units were unco-ordinated, desultory affairs, the direct result of feeble air policy decisions taken by the Asquith Government in earlier years.
This is the story of those four crucial months in the summer of 1917 – an all but forgotten period in the history of British air defence – when a few day-bombers compelled the War Cabinet not only to authorize a massive reinforcement of air defence, including the detachment of day-fighter squadrons from the Western Front at a time when they were desperately needed in France and Flanders, but also to initiate a review of the entire air organization – a review that would lead on to the formation of the Royal Air Force, a third and totally independent service, created from the amalgamation of the RFC and the RNAS.
‘The Diminished Risk’
At the end of 1916 the defenders of London, both in the air and on the ground, could look back with satisfaction on a year of successes against the conventional Zeppelins – ‘the monsters of the purple twilight’ as E. Dudley has called them. In fact, no Zeppelin had challenged the defences of the capital since the death of Mathy over Potters Bar on the night of the 1/2 October.
As time passed and the airships did not return, public confidence grew and a feeling of complacency became evident, even in Government circles. The general opinion, at quite high levels, was that the Zeppelins were finished and would never come back, and, furthermore, that the German Air Force did not then have the wherewithal to attempt long-range aeroplane raids on England. Although both ideas were fallacious (the German Navy had by no means abandoned the Zeppelin concept,* and in Belgium Kagohl 3 would soon be preparing its first assault on London), it was not really surprising to find, at the turn of the year, the Army Council, in its constant searching for replacements for the Western Front, requesting more and more men from the Home Forces Command. The military establishment at home in that autumn had no fewer than 17,000 officers and men in its AA artillery service whilst the eleven RFC home-defence squadrons mustered 110 aircraft, 200 officers and 2,000 men. Although seemingly very large, such figures belied the true state of affairs: those given for the RFC, for example, represented only about half the official establishment levels, many pilots and observers having already been sent to France since October to help make up the tremendous losses in aircrew during the Battle of the Somme, officially estimated at about 300 per cent per annum.
The run-down of the home defence forces was, in fact, to continue well into the coming spring, although many influential and knowledgeable people in the UK, including officers high in the Home Forces Command, were becoming increasingly worried about the way in which the defences were being reduced. A typical comment was voiced by the redoubtable Mr Pemberton Billing, when he stood up in the House, at the end of March 1917, and made the following forthright prediction: ‘In the next summer we shall experience raids of a much more serious character than Zeppelin raids. Aeroplanes may come over this country … at night, and at 15,000 or 20,000 feet they may drop their bombs and get back before we know where they are.’
Before proceeding further, it will perhaps be useful to consider the units, both Army and Navy, that were to contribute, however briefly, to the defence of the capital in the coming daylight campaign. The Army units involved, i.e. the RFC’s home defence squadrons, the AA artillery Commands and the observation and warning organizations, were all part of the Home Forces Command under Field-Marshal Lord French, with Major-General Sir Frederick Shaw as Chief-of-Staff.
Firstly, then, we may look at the organization of the RFC’s Home Defence Wing, the aeroplane being rightly regarded by the Army as the main plank in its anti-aircraft strategy, although the Admiralty, during it tenure of the defence office, had thought otherwise. The Home Defence Wing, now commanded by Lieutenant-Colonel T. C. R. Higgins, the former CO of No. 39 (Home Defence) Squadron, consisted of eleven active squadrons with one in reserve, but of these only Nos. 37, 39, 50 and 78 could have been regarded as defenders of London. The disposition of a home defence squadron was usually as follows . . .
* The surviving conventional Zeppelins were being modified to enable them to operate at 20,000 feet, a height that would be quite impossible for the existing types of defence aircraft to attain. These high-altitude airships were, in fact, sent on a raid to London (the so-called ‘Silent Raid’) on 19 October 1917, i.e. almost a year after the loss of Mathy. Fortunately for the city, and quite fortuitously, the raiders were dispersed, after only a few bombs had been dropped, by an unexpected gale arising. It is certain that the defences could not have prevented what might have been ‘an appalling disaster’.