The RAF begins bombing the Ruhr

On 15 May 1940, the sixth day of the German offensive in the west, the British War Cabinet under Winston Churchill lifted the ban that had tied the hands of Britain’s bomber force since the beginning of the war. RAF Bomber Command was given permission to attack targets east of the Rhine, in the very heart of German industry: the synthetic fuel plants, marshalling yards and steelworks of the Ruhr. That same night, 15–16 May, 99 bombers set out for the Ruhr. It was the first large British raid on Germany’s industrial base and the conventional starting point of the strategic bombing offensive against Germany, which was to last almost five years. The decision was taken the day after the Luftwaffe bombed Rotterdam, and under the impression of that event.

This raid is usually linked with reprisal for Rotterdam, and Gelsenkirchen is named as the first target, followed in the next few days by Hamburg, Bremen, Cologne, Essen, Duisburg, Düsseldorf and Hanover. The general picture is right but needs two qualifications. Rotterdam settled the timing, not the principle, since the Allies had already agreed in April on raids on the Ruhr in the event of a German attack on the Netherlands or Belgium. And in May 1940 the targets were not the cities as such, but individual plants and railway junctions, often on their outskirts.

Bombers on a leash

For the first eight months of the war British bombers did not drop a single bomb on German industry. On 1 September 1939 President Franklin Delano Roosevelt appealed to the belligerents not to bomb civilians or undefended towns. Britain and France accepted this undertaking at once. Behind the noble declaration, however, lay a sober calculation: the Luftwaffe, whose strength the Allies overestimated, might answer the first bombs with raids on London and Paris, and Britain’s bomber force was still small and poorly prepared. Bomber Command therefore attacked only warships at sea and in roadsteads, and over Germany it dropped leaflets. The first RAF raids on warships off Wilhelmshaven on 4 September 1939 and the air battle over the Heligoland Bight on 18 December showed, moreover, that bombers without fighter escort could not survive over Germany by day. From then on the heavy aircraft flew mainly at night.

This policy could be grotesque. The Conservative MP Leo Amery recalled that when, in the autumn of 1939, he suggested to the Secretary of State for Air, Kingsley Wood, setting fire to the forests of the Black Forest, where the Germans stored ammunition, he was told that this was out of the question because the forests were private property. The RAF attacked its first target on German soil, the seaplane base at Hörnum on the island of Sylt, only on the night of 19–20 March 1940, in retaliation for the German raid on Scapa Flow.

An attack on the Ruhr, which produced about two-thirds of Germany’s steel and a large part of its coal and had been planned before the war, was blocked by France. At meetings of the Supreme War Council in November and December 1939 the French rejected the British proposal to bomb the Ruhr if the Germans entered Belgium: they believed such raids would not stop an invasion but would provoke Luftwaffe reprisals against French cities and factories. Only at the meeting in Paris on 22–23 April 1940 was it agreed that if Germany attacked the Netherlands or Belgium, the RAF would bomb the Ruhr without further consultation. That same month Charles Portal, an advocate of striking at German industry, took over Bomber Command.

Five days of hesitation

When Germany attacked in the west on 10 May 1940, the April agreement was not put into effect at once. Fairey Battle and Bristol Blenheim light bombers were thrown against German columns and bridges in the Netherlands, Belgium and France, where they suffered enormous losses. On the night of 10–11 May heavier aircraft from bases in England attacked roads and railway lines west of the Rhine. According to the RAF Museum’s chronology, eight Whitleys of Nos. 77 and 102 Squadrons then carried out the RAF’s first deliberate raid on German territory on the Continent. On the night of 11–12 May some 36 Whitleys and Hampdens bombed roads and the railway station at Mönchengladbach, through which German reinforcements were passing on their way to Belgium. Four people were killed, among them an Englishwoman living in the town. Some German and British studies regard this raid as the first British bombing of a German city.

The Germans, meanwhile, already had a propaganda victim of their own. On the afternoon of 10 May three German He 111 bombers that had lost their way en route to Dijon dropped their bombs on Freiburg im Breisgau, mistaking it for the French town of Colmar. Fifty-seven people were killed. Goebbels’s propaganda at once blamed the raid on the Allies and announced that the Luftwaffe would answer every such “criminal attack” fivefold. The truth was established only after the war.

In London the argument went on. Churchill’s new government, formed on 10 May, discussed bombing on 12 May. Churchill declared then that Britain was no longer bound by its former scruples about starting “unrestricted” air warfare. The next day he was opposed by Neville Chamberlain, now Lord President of the Council, who feared German reprisals against British cities. The Air Staff pointed out how small Bomber Command was. The events of 14 May settled the matter. The Germans broke through the front at Sedan, and in the afternoon Luftwaffe bombers burned down the centre of Rotterdam. News reached London of tens of thousands dead; Dutch legations gave figures of between 30,000 and 100,000. In reality, according to later findings, between about 800 and more than a thousand people were killed, but throughout the war Rotterdam was regarded around the world as a symbol of German terror from the air.

The decision of 15 May

On the morning of 15 May the French prime minister, Paul Reynaud, telephoned Churchill and said: “We are beaten; we have lost the battle.” The French were demanding more fighter squadrons. That same day the head of Fighter Command, Hugh Dowding, argued before the Chiefs of Staff Committee that sending further fighters to France would not decide the battle but would strip Britain’s own defences bare. The War Cabinet looked for another way to help its ally and found it in the bombers. After consulting the Chief of the Air Staff, Cyril Newall, and the Secretary of State for Air, Archibald Sinclair, it authorised night raids on targets east of the Rhine. The Air Ministry passed Portal a list of targets: first and foremost the coal hydrogenation plants, that is, the works producing synthetic petrol on which the German army depended, and also marshalling yards and steelworks, which at night gave away their own positions by the glow of their furnaces.

Two calculations lay behind the decision. The first was economic: destroying the fuel plants was in the longer run to paralyse German tanks and aircraft. The second was operational. London hoped that raids on the Ruhr would force the Luftwaffe to pull fighters and anti-aircraft guns back from the front, or provoke it into attacking Britain, where Fighter Command was waiting for it, rather than the troops in France. Churchill set this out to Reynaud in a letter of 16 May: British experts were agreed that it was better to draw the enemy onto the island by striking at his vital centres, and in this way to aid the common cause.

The first night over the Ruhr

On the evening of 15 May 99 aircraft took off from airfields in eastern England: 39 Wellingtons, 36 Hampdens and 24 Whitleys. For the Wellingtons it was the first night bombing operation of the war. They were to strike 16 targets (some sources say 18). Seventy-eight crews were sent against fuel plants, above all the synthetic petrol works at Gelsenkirchen, Oberhausen, Castrop-Rauxel, Wanne-Eickel, Dortmund and Bottrop. The rest were to attack marshalling yards and steelworks.

The bombers flew singly, not in close formation, each crew navigating for itself with map, compass, calculation and whatever it could see below. Over the Ruhr, permanently shrouded in factory smoke and haze, this proved extremely difficult. According to Bomber Command’s figures, only 24 of the crews sent against the fuel plants reported finding their targets, although fires were seen in several places. The rest dropped their bombs on alternative targets or where they expected the target to be. German defences shot down no aircraft. One Wellington of No. 115 Squadron strayed off course on the way back and crashed into hills near Rouen in France; five airmen were killed.

The damage in the Ruhr was slight. The refineries and fuel plants kept working, and bombs that fell far from their targets hit fields, houses and streets. It was in these first weeks that German civilians in the Ruhr came to know the air war: the sirens often failed, and bombs fell without warning, which, according to reports by the SS security service, caused anxiety and rumours, including talk of gas.

The following nights

Bomber Command continued its raids on the following nights, though with smaller forces. On the night of 16–17 May twelve aircraft again attacked fuel plants in the Ruhr. On the night of 17–18 May 48 Hampdens went for the oil installations at Hamburg-Harburg and 24 Whitleys for works at Bremen. These operations began a long series of raids on both great ports. On the night of 18–19 May 60 bombers attacked refineries and railway lines. Through the rest of May and in June British bombs fell on plants and railway stations around Cologne, Essen, Duisburg, Düsseldorf and Hanover, and a single bomber attacked the works at Leuna near Leipzig as early as the night of 22–23 May. A particularly frequent target was the railway junctions at Hamm, through which most traffic from the Ruhr passed; between May 1940 and August 1941 the British tried to hit them on more than a hundred nights.

The “strategic” offensive of May 1940 was, however, modest and intermittent. As the German panzer divisions drove towards the Channel, much of Bomber Command’s strength reverted to tactical tasks: heavy bombers attacked bridges, roads and communication centres behind the German front in France and Belgium at night. Nor did the Luftwaffe allow itself to be drawn back to Germany. It neither withdrew fighters from the front nor struck at England, but went on supporting the advance of the ground forces. The main operational aim of the decision of 15 May was not achieved, and German fuel production hardly suffered.

Place in the war

The night of 15–16 May 1940 is regarded as the beginning of the British strategic bombing offensive. It ended only in the spring of 1945. For a long time crews and commanders believed they were hitting the plants marked for them on their maps. Only the Butt Report of August 1941, based on aerial photographs, showed that just one crew in three was dropping its bombs within eight kilometres of the target, and over the Ruhr only one in ten. Out of this helplessness grew the strategy of area bombing of whole cities, pursued from 1942 by Arthur Harris. In the spring of 1943 Bomber Command fought the “Battle of the Ruhr”, in the summer of that year it burned Hamburg, and in the last months of the war, together with the American air forces, it reduced most of Germany’s large cities to rubble. According to various estimates, Allied bombing killed between about 350,000 and more than 500,000 civilians in Germany. Bomber Command lost more than 55,000 airmen.

The decision of 15 May also had a propaganda dimension. German propaganda presented the British raids as “terror attacks” on a defenceless population and linked them with the invented guilt for Freiburg. As late as December 1940 Adolf Hitler was accusing Churchill of having been the one to start bombing German civilians, and in September of that year he had threatened to “erase” British cities in retaliation for the British raids. The truth was different. The Luftwaffe had earlier bombed Wieluń and Warsaw, and, the day before the decision, Rotterdam; the first British raids on the Ruhr were aimed at industrial plants and killed few people. They showed, however, that the line both sides had observed in the west since September 1939 no longer existed. In the years that followed, the targets, which in May 1940 had been individual refineries and marshalling yards, came to include entire cities.