“A historian has dubbed the night, ‘one of the biggest fiascos in British air defence history.’ The population of the Midlands now realized just how defenceless they were in the face of aerial attack, leading to questions at all levels.”

By Ian Castle

WHEN BRITAIN declared war on Germany in August 1914, military planners in London were well aware that the enemy possessed a unique weapon — giant rigid airships. The best known of these were the Zeppelins, although there were a smaller number built by a rival company — Schütte-Lanz. 

For some years, Zeppelin airships had operated as civil airliners, offering enthusiastic travellers a birds-eye-view of the countryside of Germany, Austria and Switzerland. It was not long before the German military recognized their potential as a weapon of war. At a time when aeroplanes were but flimsy structures of wood, wire and linen, the sleek, giant rigid airships of Germany appeared to embody the true future of aviation. 

At the start of hostilities, the German military had two airship fleets: one for the navy and one for the army. As the war progressed it was the navy Zeppelins that pursued the air war against Britain with the greatest conviction, although the honour of being the first to bomb London went to an army Zeppelin in May 1915. 

Throughout 1915, German airships encountered little in the way of serious opposition when they appeared over Britain. The nation had trailed in aviation development prior to the outbreak of war and had also given little consideration to creating an aerial defence plan. 

When war broke out the army’s Royal Flying Corps (RFC) departed for Europe with the British Expeditionary Force, with responsibility for aerial defence being taken up by the Admiralty through the Royal Naval Air Service (RNAS), albeit on the understanding this was to be a temporary arrangement. They had at the time an eclectic collection of about 50 serviceable aircraft — both landplanes and seaplanes — and air stations around the coast. In addition, they occupied airfields at Hendon, north-west of London, and at Chingford, north-east of the capital, from where aeroplanes could defend the city. 

German airships bombed Britain on 20 occasions in 1915, during the course of which only one Zeppelin was lost. Navy Zeppelin L 12, damaged by AA fire from Dover, came down in the sea intact but was accidentally destroyed by fire after being towed into Ostend harbour. Otherwise, the raiders largely escaped unscathed and notably bombed London on five occasions. In total that year the raiders dropped about 35 tons of bombs — both high-explosive and incendiary — inflicting 740 casualties (208 killed and 532 injured) and causing damage estimated at the time at about £815,000. A single raid on London in September 1915 was responsible for 65 per cent of the year’s total material damage. It was that raid that led to the recognition that Britain’s air defences needed urgent improvement. Immediate steps were taken by the Admiralty to increase and improve the available AA guns, although this mainly focused on the defence of London. Also at this time, under pressure from the Secretary of State for War, Lord Kitchener, the RFC was ordered to support the RNAS in offering opposition to the raiders even though officially it was not their responsibility. 

In fact, the clock was ticking for the end of the Admiralty’s ‘temporary’ role in safeguarding Britain’s airspace; by the end of 1915 it had been handling the file for 16 months. The transfer of responsibility from the Admiralty to the War Office finally took place in February 1916, although the RNAS would continue to seek the raiders while over the sea and the RFC would engage those that penetrated inland. 

Interestingly, on the eve of the transfer — the night of Jan. 31, 1916 — nine naval Zeppelins raided England’s industrial Midlands, fully exposing the inadequacies of Britain’s defence for all to see. It would become known as the Great Zeppelin Raid. 

There was not a single anti-aircraft gun defending the towns that were targeted; poor weather ensured most RNAS aircraft remained on the ground. Because the destination of the Zeppelin raiders was unknown, warnings were widely disseminated with disastrous results. 

At airfields around London the RFC responded by flying 13 sorties. With heavy mist blanketing the airfields, two RFC pilots were fatally injured, two more suffered minor wounds, five aircraft were wrecked and two damaged. Yet no Zeppelin passed within 70 miles of London. 

The authorities recorded the fall of 379 bombs and estimated the material damage at around £54,000, with 70 people killed and 113 injured. A historian has dubbed the night, “one of the biggest fiascos in British air defence history.” The population of the Midlands now realized just how defenceless they were in the face of aerial attack, leading to questions at all levels. It was now apparent that Zeppelins intended venturing further inland than they had done previously and following the transfer of responsibility for aerial defence to the War Office, the outcome of this most recent raid signified an urgent need for change.  

While Britain had a policy of lighting restrictions across the country, final decisions were left to each local authority. During this latest raid, while some towns remained in darkness others left their lights shining brightly, serving as a beacon to the Zeppelin raiders. Steps were introduced to widen the lighting restrictions and improve the warning system to give notice of likely raids as early as possible — this was essential for those vital war industries whose workers were beginning to refuse to work at nights without this early notice. The first steps in this new warning system were introduced in February, the whole scheme in operation by May 1916. 

The plan divided England, Wales and part of Scotland into eight Warning Controls, each under a Warning Controller. These eight controls were sub-divided into 54 numbered warning districts, with each of these very roughly 30 to 35 miles square. The principal was that at a generously presumed speed of 60 mph, a Zeppelin would take about 30 minutes to cross a district, allowing those in the path of a Zeppelin to receive alerts in succession. This ensured factory work could continue until a raid seemed inevitable while allowing enough time for the affected workforce to take shelter. Cordons of observers positioned to cover all approaches could telephone information directly to the warning controller for the region. The controllers also received information from General Headquarters Home Forces, anti-aircraft gun stations and from adjoining warning controllers, as well as from the police, railway officials and any military commands in his area. When introduced the system generally worked well, giving adequate warning of potential raids. 

As well as increasing the number of anti-aircraft guns available and the installation of batteries in new locations, attention was also paid to searchlights. Previously most had worked directly with the guns, but new ‘aeroplane lights’ were also established to illuminate targets not for batteries but for the aircraft defending London. There were also searchlight barrage lines in Kent, Essex and Norfolk on the routes to London from the coast. Plans were also approved to create more RFC squadrons specifically for Home Defence and for a line of airfields from the north to the south of Britain generally about 20 miles apart supported by an increase in emergency landing grounds where pilots in trouble who could not reach their home bases were able to put down safely.  

There was one final piece of the jigsaw that would destroy the myth of invincibility that surrounded the Zeppelins — new bullets for the Lewis machine gun carried by Home Defence aircraft. Zeppelins, up to 645 feet long, contained up to two million cubic feet of highly flammable hydrogen gas, presenting a huge and seemingly vulnerable target. The task of bringing one down would therefore appear to be a simple one. But in fact that was not the case. Hydrogen only becomes flammable when mixed with oxygen. The gas keeping a Zeppelin aloft was contained in as many as 19 separate cells within the body of the airship. If a standard lead bullet pierced one, only a small amount of hydrogen would escape and there would be no spark to ignite it. Accordingly, the initial doctrine was for a pilot to get above the Zeppelin and drop bombs or explosive darts on it. That was easier said than done because airships could easily outclimb the ponderous aircraft sent up to attack them.

A solution came in mid-1916 when new bullets were added to the arsenal of the aircraft defending Britain. Rounds like the Pomeroy and the Brock, with both explosive and incendiary attributes, as well as the Buckingham incendiary bullet were deployed. They proved to be a critical advance. Although none of the rounds on their own appeared completely effective, when loaded together in sequence in the same ammunition drum they posed a genuine threat.

The idea was that an explosive bullet would blow a hole in the gas bag, letting hydrogen escape to mix with oxygen, and a following incendiary bullet would then ignite the now volatile gas. In July 1916, following encouraging trials, RFC pilots abandoned their bombs. It was the beginning of the end of the Zeppelin threat to Britain. 

With early warning of approaching Zeppelins on the night of Sept. 2, 1916, the RFC Home Defence squadrons were airborne and patrolling. Searchlights sweeping the sky found an airship north of London and the anti-aircraft guns opened fire. The lights and exploding shells in the sky attracted the pilots and one, firing a burst of new bullets, shot down the first German airship on British soil — not a Zeppelin this time, but an army Schütte-Lanz. Within the next four weeks Britain’s air defences added three Zeppelins to their bag, then two more in November. 

Following the 20 Zeppelin raids in 1915, there had been 21 in 1916, but now the threat was all but over. Navy Zeppelins continued raiding in 1917, but only on six occasions. Only three raids took place in 1918. The changes introduced in the wake of the Great Midlands Raid had brought an end to the Zeppelin menace. But the threat to Britain from the air had not diminished. In 1917 the German Army had abandoned Zeppelin raiding completely and switched their attention to bomber aircraft; in May 1917 they launched the Gotha bomber against Britain, with London as the prime target. It was back to the drawing board for Britain’s defenders.

Ian Castle is the author of the upcoming Zeppelin Inferno – The Forgotten Blitz 1916. He has been writing about military history for over 30 years but for the last 15 he has focused on the German air raids on Britain during the First World War. Zeppelin Inferno, which is due for publication in April, is the first in a three-volume series. Other works include Zeppelin Onslaught – The Forgotten Blitz 1914-1915, The First Blitz – Bombing London in the First World War and The First Blitz in 100 Objects. He also has an extensive website on the raids at www.IanCastleZeppelin.co.uk