The Bombers and the Bombed: Allied Air War Over Europe 1940-1945

by Richard Overy

The modern aerial bomb, with its distinctive elongated shape, stabilizing fins, and nose-fitted detonator, is a Bulgarian invention. In the Balkan War of 1912, waged by Bulgaria, Greece, Serbia, and Montenegro (the Balkan League) against Turkey, a Bulgarian army captain, Simeon Petrov, adapted and enlarged a number of grenades for use from an airplane. They were dropped on a Turkish railway station on October 16, 1912, from an Albatros F.2 biplane piloted by Radul Milkov. Petrov afterward modified the design by adding a stabilizing tail and a fuse designed to detonate on impact, and the six-kilogram bomb became the standard Bulgarian issue until 1918. The plans of the so-called Chataldzha bomb were later passed on to Germany, Bulgaria’s ally during the First World War. The design, or something like it, soon became standard issue in all the world’s first air forces.

The sharp lesson was to be a heavy bombing attack on Sofia. Churchill justified the operation on political grounds: “Experience shows,” he told the meeting, “that the effect of bombing a country where there were antagonistic elements was not to unite those elements, but rather to increase the anger of the anti-war party.”6 Others present, including Air Chief Marshal Sir Charles Portal, chief of the air staff, and the chief of the imperial general staff, General Alan Brooke, were less keen and insisted that leaflets should be dropped along with the bombs explaining that the Allies wanted Bulgaria to withdraw its occupation troops and surrender (in the end leaflets were dropped with the curious headline “This is not about Allied terror, but about Bulgarian insanity”).

For the unfortunate populations in the way of the bombing, in Italy or France or Romania, there was never much point in trying to work out whether they had been bombed strategically or not, for the destructive effects on the ground were to all intents and purposes the same: high levels of death and serious injury, the widespread destruction of the urban landscape, the reduction of essential services, and the arbitrary loss of cultural treasures. Being bombed as part of a ground campaign could, as in the case of the French port of Le Havre in September 1944 or the German city of Aachen in September and October the same year, produce an outcome considerably worse than an attack regarded as strategically independent.

One reason why the RAF stuck with the idea that a powerful striking force of bombers would be the most effective way to exploit the potential of airpower can be found in the nature of the combat experience enjoyed by British airmen in the interwar years. Instead of drawing lessons from the Spanish Civil War about the advantages of close-support aviation and air superiority, which was the conclusion drawn by most other air forces, RAF doctrine was mainly informed by the experience of what was called air policing in the empire or Afghanistan.54 The use of aircraft to enforce local control against rebel tribes and tribesmen (described in the Manual as war against “semi-civilised peoples”) was taken as a paradigm to explain what might happen if a civilized state was subjected to a heavier level of bombing. Even tribal communities, it was argued, had vital centers that governed their existence; target intelligence on those centers would allow the small light bombers allocated to the operation to destroy them and, in doing so, to compel compliance from unruly subjects. John Slessor, director of plans in the Air Ministry in the late 1930s, gave a brutally frank description in his memoirs of why air policing worked: “Whether the offender concerned was an Indian Frontier tribesman, a nomad Arab of the northern deserts, a Morelli slaver on the border of Kenya, or a web-footed savage of the swamps of the southern Sudan, there are almost always some essentials without which he cannot ...

This perception of bombing serves to explain the wide gap between the strategic vision at the heart of the interwar RAF and the reality of British bombing capability and defense strategy in the 1930s. Imperial air policing was undertaken in conditions of clear visibility, little or no opposition, and low-level attack, none of which would be true of an aerial offensive undertaken in Europe. As a result, colonial practice did not persuade Britain’s military leaders to bank everything on the bomber. Indeed, fear of bombing, particularly once Hitler’s Germany had been identified in the mid-1930s as the most likely potential enemy, acted as a powerful spur to change British priorities in the air to one that was more appropriately defensive. When the military Joint Planning Committee was asked in 1934 to estimate the probable effects of a German “knockout blow” from the air, it was assumed that a week of bombing would produce 150,000 casualties and render millions homeless. Later estimates by the chiefs of staff continued to assume that these statistics were realistic—more than a match for the alarmist literature of the age.58 In 1937 the newly appointed minister for the coordination of defense, Sir Thomas Inskip, told the RAF that the role of the air force was not to inflict a knockout blow on the enemy (which it was incapable of doing) “but to prevent the Germans from knocking us out.”59 The Committee of Imperial Defence spelled out guidelines for air strategy in which the air...

The short campaign against Bulgaria illustrated the tension that existed between the exaggerated expectations of politicians and the public about the likely political and psychological results from attacking an enemy from the air and the demonstrable value in military and economic terms of doing so. This ambiguity underlay many of the wider wartime arguments between politicians, airmen, and the military chiefs over what bombing could or could not deliver, and it helps to explain a feature characteristic of all bombing campaigns: the escalation of the degree of indiscriminate damage.

The pattern of bombing in Bulgaria, from a limited raid on Sofia’s railway facilities and the Vrajedna airfield in November 1943 to the final raids in March and April 1944 when the extensive use of incendiaries produced much higher levels of urban destruction, was not an accidental progression. In all the major campaigns in Europe (and in the campaigns mounted in eastern Asia) there occurred an evident escalation the longer the bombing went on and the more uncertain were its results.

The reasons for escalation differ in historical detail from case to case. Nevertheless, they suggest a common process dictated partly by technical frustration at poor accuracy and navigation or high losses; partly by political frustration at the absence of unambiguous results; partly by air force anxiety that failure might reflect badly on its claim on resources; and finally, and significantly, by the slow erosion of any relative moral constraints that might have acted to limit the damage to civilian targets.

There can be little room for doubt that the experience of bombing was deeply demoralizing for many of those who survived it, though it could also provoke sudden moments of exhilaration, or induce a profound apathy, but the difficulty in drawing any clear causal links between bombing and popular response is simply that the response was as varied, irregular, unpredictable, and diverse as the society that made it. The social reaction to bombing is often treated as if it must be uniform, but it differed widely between states and within communities. This was a reality seldom appreciated by those doing the bombing, for whom “Germans” or “Italians” or even “Bulgarians” became simply a generic description of the human target. One of the key questions still debated about the bombing war is why the bombed societies did not collapse at once under the impact, as conventional wisdom before 1939 suggested they would. This is too simple an approach. Bombing did place enormous strains on local communities, and some did experience a cumulative or temporary social breakdown as a result, but it was always a long step from local social crisis to the complete collapse of a war effort. To understand why “morale” did not collapse in Germany in any meaningful way, but evidently declined in Italy prior to surrender in 1943, is to engage with complex issues of social cohesion defined by regional differences, the intensity of the bombing experience, the nature of the prevailing state and local admin...

This is one of the most important paradoxes raised by the fact of the Anglo-American bombing war. Both were liberal states committed in the 1930s to trying to keep the peace, both were states in which there was widespread public condemnation of bombing civilians, whether in Ethiopia, China, or Spain, yet in both the idea of destroying the “vital centers” or the “social body” was most fully elaborated. Part of the explanation lies in the geopolitical and military realities confronted by both states. Force projection for both had seldom involved a large army, and the army remained, even after the Great War, a component of the defense establishment rather than its driving force, as it was in France, Germany, or the Soviet Union.

There was also in both Britain and the United States a real attraction for the idea that air warfare was a more modern and efficient form of fighting than the recent experience of a grueling and costly land war. Since both were democracies, with political elites sensitive to popular anxieties and expectations, airpower was intended to reduce the human cost of war on the ground. Arthur Harris famously argued that the army would fail next time to find “sufficient morons willing to be sacrificed in a mud war in Flanders,” but for Germany, France, or the Soviet Union, a ground army and effective ground defenses were essential elements in their security planning.69 The idea that modern technology and science-based weaponry enhanced military efficiency was central to the American view of the potential of a bombing

The modernity of airpower was emphasized in other states as well, for propaganda reasons as well as military ones, but much less autonomy was allowed to those air forces to campaign for strategies that could be presented as more efficient and less costly than traditional surface combat with armies and ships.

Although the term “total war” was first popularized by Erich Ludendorff, the German general who had masterminded much of Germany’s war effort between 1916 and 1918, it was appropriated as a description of whole societies at war much more fully in Britain and America than it was in continental Europe. “There can be no doubt,” wrote the British aviation journalist Oliver Stewart in 1936, “that a town in any industrial civilisation is a military objective; it provides the sinews of war; it houses those who direct the war; it is a nexus of communications; it is a centre of propaganda; and it is a seat of government.”72 As a result, he continued, “blind bombing of a town as a town might be logically defended.” In a lecture to the Naval Staff College, also in 1936, Air Vice Marshal Arthur Barratt asked his audience to recognize that it was no longer possible “to draw a definite line between combatant and non-combatant.” This was, he claimed, a result of the “power of democracy”; the more governments depended on the support of the governed, the more the morale and resources of the civil population became a legitimate object of attack.

It may be that in both Britain and the United States popular public fears about a war from the air were more powerfully and publicly expressed, given the previous geographical immunity both states had enjoyed before the coming of the airplane and full freedom of expression, and that as a result popular phobias fueled military speculation that bombing the home front would have immediate results.

The standard British 250- and 500-pound bombs had a low charge-to-weight ratio (around one-quarter was explosive, against one-half in German bombs), but they also contained less destructive explosive content, without the addition of aluminum powder (standard in German bombs), and were prone to fail to detonate.

The technical level of the force that went to war in 1939—aircraft, bombs, and equipment—can be described charitably as unsophisticated.

The only operations permitted in German airspace were propaganda runs dropping millions of leaflets. Some aircrews, struggling to cope with the excessive cold, chucked out the heavy bundles without cutting them first, making them a potentially more lethal weapon than had been intended.

The nighttime flights posed all kinds of difficulties. Interviews with operational crews confirmed that intense cold and long, risky flights over sea were compounded with the difficulty experienced over Germany itself, which they found to be “very black.” It proved almost impossible to find and hit a specific target in the midst of the blackout, even with leaflets, a fact that RAF planners had already realized some months before when drawing up a “Night Plan” to accommodate the shift from daylight to nighttime operations, in which it was admitted that hitting anything “will be largely a matter of chance.”

Most explanations for the start of the British campaign have assumed that it was a response to the German bombing of Rotterdam on May 14, but the first raid, on Münchengladbach, had already taken place three days before, while Rotterdam was not mentioned in any of the cabinet discussions about initiating the bombing of German targets. The decision was taken because of the crisis in the Battle of France, not because of German air raids.24 The actual circumstances surrounding the onset of bombing were more complex. By chance the German attack in the west on May 10, 1940, began on the same day that the Chamberlain government was replaced by a new one headed by Winston Churchill. Chamberlain had always opposed the use of bombers against urban targets, but Churchill had no conscientious or legal objections. As minister of munitions in 1917, he had been a prominent supporter of an independent air force and a campaign of long-range bombing against German industrial objectives. Later, as minister for air after the war, he had played a key role in securing the independent future of the RAF. He accepted the argument that bombing could be expected to produce important strategic results. A government headed by Churchill rather than Chamberlain was always more likely to endorse a bombing campaign.

The onset of the German “Blitz” is often regarded as the trigger for British attacks on German urban areas, but there had already been growing pressure from Bomber Command to be allowed to bomb less discriminately.

Both the accuracy and power of British bombing and its capacity to inflict decisive material and psychological damage on Germany were presented in terms quite incompatible with the reality of Bomber Command’s strength, range, and capability. The detailed study on the Ruhr bombing suggested that somewhere between 1,000 and 4,000 sorties were all that were required to knock it out. Calculations suggested that eight bomb hits would eradicate a power plant, sixty-four hits destroy a coking plant, and twelve hits destroy an aqueduct; average bombing error was given as seventy-five yards (sixty-nine meters) from low level and 300 yards (276 meters) from high altitude, figures that had never been verified under combat conditions (and proved entirely unattainable in practice).

To abandon the principle that killing civilians from the air was wrong owed a good deal to the British perception of the German enemy. The legal issue involved was sidestepped by two arguments: first, that the Germans had begun unrestricted bombing and would do it again, given the chance; second, that Hitler’s Reich represented such a profound menace to Western civilization that the greater moral imperative was to use every means available to destroy it. The view that the Germans were responsible for bombing civilians first had a long pedigree, stretching back to the Zeppelin and Gotha raids of the First World War, which many RAF commanders had experienced as young officers just over twenty years before. During the 1930s, popular prejudices revived about German science and the German military conniving to produce lethal weapons of mass destruction to be unleashed from the air on an unsuspecting opponent.41 The bombing of the Basque town of Guernica in April 1937 by the German Condor Legion was popularly regarded in the West as evidence that the Germans had once again abandoned any pretense of civilized behavior. The campaign in Poland was scrutinized for evidence that German bombers were deployed for terrorizing and murdering civilians. Although the evidence was ambiguous, since it was understood that the German raids were directed at military targets as part of a combined-arms ground campaign, the RAF preferred to assume that the Germans had bombed indiscriminately. A rep...

The assumption in all the discussions about restricting bombing was that it had force only so long as the enemy observed the same limitation, and in this sense Poland played an important part in paving the way for British action. Of course, German bombers had not yet bombed British cities, so the argument for attacking Germany came to be based on preemptive retaliation.

When a German raid on the Royal Navy base at Scapa Flow in March 1940 killed a nearby cottager (the first civilian casualty of the war), Churchill angrily berated the Air Ministry for not giving it maximum publicity as the likely start of “deliberate horror raids on civilians,” for which the Germans would carry the blame.45 In April the propaganda department of the new Ministry of Economic Warfare recommended describing German reconnaissance missions as frustrated bombing raids—“driven off before they were able to drop their bombs”—so as to justify any British retaliation.46 In May 1940 one of the arguments for bombing Germany was that sooner or later German leaders would do the same when it suited their strategic interests. “Do [the government] think,” wrote one bombing lobbyist, Marshal of the RAF Sir John Salmond, “that Hitler, who does not consider for a moment the slaughter of thousands on the ground and of devastating countries with which he has no quarrel, will shrink from killing civilians in this country?”47 In the cabinet discussion on May 15, Sir Hugh Dowding, commander in chief of Fighter Command, argued in favor of anticipatory attacks because he felt convinced that sooner or later the German Air Force would start indiscriminate bombing.48 Yet very soon the argument that Germany started the bombing became the standard version, both among the wider public and in the RAF, and it has remained firmly rooted in the British public mind ever since.

Many prominent churchmen, politicians, and intellectuals who might have condemned bombing under different circumstances supported it as a necessary evil. For people who were already predisposed to see the German threat in crude moral terms, it was a relatively simple step to the argument that the greater moral obligation was to secure the continued freedom of the West than to abstain from killing German civilians.

Yet between January and June 1940 only two aircraft were claimed from antiaircraft fire, and in August and September not a single one.

Most of Bomber Command’s problems were self-inflicted. A postwar presentation of the early bombing effort by an official of the British Bombing Survey Unit in 1946 concluded that the forces were too small, the weapons incapable of a high degree of damage, targets could not be found, and too much effort was devoted to subsidiary operations: “great call on Air Force,” ran the lecture notes, “to attack and destroy targets beyond its power.”

His enthusiasm for bombing was a creature of the emergency facing Britain during the summer and autumn of 1940 when British forces had to demonstrate to the United States and to the peoples of occupied Europe that they still had some capacity for offensive action, however limited. It was also necessary to impress the British public that military action against Germany had not been abandoned after the evacuation from Dunkirk in late May and early June.

Bomber Command achieved negligible results against German targets and invited German retaliation. In early September, Hitler finally responded to British attacks by permitting a campaign against London and other cities that dwarfed anything that could be done in return. Between September 1940 and June 1941 more than 57,000 tons of high-explosive and incendiary bombs were dropped, principally on British port cities, which absorbed 85 percent of the tonnage. Around 43,000 people were killed in the ten-month campaign, more than ten times as many as were killed by RAF raids on Germany in the same period. It is possible that the Blitz would have been launched anyway, as British air leaders had expected, but it is also possible that without a British bombing campaign over the summer of 1940, British cities might have been spared the full horrors of the winter of 1940–41.

The onset of heavy German night bombing in September 1940 showed Bomber Command at last what a serious bombing offensive looked like. Attacks were made with hundreds of bomber aircraft concentrated against a single target, while diversionary or nuisance raids were made to confuse the defenses and create widespread disruption. Heavy use of incendiaries contrasted with the British preference for high-explosive bombs, and produced widespread area damage. At first the RAF thought the German campaign was flawed, because it assumed the attacks were designed to terrorize the population. “Notes on the Lessons to Be Learned from German Mistakes,” a survey produced two weeks after the first heavy raid on London, concluded that “the indiscriminate attack of cities is invariably uneconomical,” a view with which German air commanders would have concurred.74 But it soon became clear that the pattern was to attack ports, food supplies, and the aircraft industry, and the evident ability of German bombers to attack at will and achieve a relatively high concentration of hits turned the RAF toward the idea of learning lessons from what the Germans got right.

The shift in 1941 and 1942 to a policy of “area” bombing came about not as a result of the poor accuracy achieved in attacks on specific objectives, as is usually suggested, but by copying the Germans. The German offensive was from this point of view a valuable learning tool, since it was difficult to evaluate clearly what Bomber Command was itself achieving over Germany. From June 1940 onward, Britain was cut off from Europe by German military successes. Until the autumn the RAF relied on hearsay and occasional news reports to form a picture of the effects of British bombing.

“It is axiomatic,” ran the report, “that fire will always be the optimum agent for the complete destruction of buildings, factories etc.” The department recommended using high-explosive bombs to create the “essential draught conditions” in damaged buildings, followed by heavy incendiary loads, and completed with more high explosive to hamper the enemy emergency services.76 The evidence that concentrated use of incendiaries was the most effective form of air assault against large industrial centers gradually emerged as the key lesson to be learned from the experience of the Blitz.

The politicians, Churchill included, generally understood morale in political terms: heavy pressure from bombing would induce a social and political collapse, perhaps even a revolution. The German attacks on morale were more clearly economic in intent. In May 1941 the Ministry of Economic Warfare, which had been monitoring the ineffective impact of Bomber Command on precise economic objectives in Germany, sent a memorandum recommending that the RAF abandon military targets and focus instead on economic warfare against major industrial concentrations or “whole cities.” The idea stemmed from the effects of German bombing on the British workforce: “British experience leads us to believe that loss of output . . . through absenteeism and other dislocation consequent upon the destruction of workers’ dwellings and shopping centres is likely to be as great as, if not greater than the production loss which we can expect to inflict by heavy damage.”84 Although the hope for a political dividend from bombing was not abandoned entirely, particularly by Churchill, the Air Ministry came to view morale as a barometer of productive performance rather than political outlook. The same term was used to cover both, but by the time morale became a specified objective in July 1941, it was used as a description of economic attrition—a form of “industrial blockade”—in which the working-class population was attacked as an abstract factor of production whose deaths, disablement, or absence would hav...

Later in 1941, when calculations were made of the ratio between weight of bombs and expected deaths among German workers, the measurements were given as “1 Coventry,” “2 Coventries,” and so on; an attack on the scale of “4 Coventries” was expected to yield 22,515 German deaths.87 It is important to recognize that the emphasis on killing German workers and destroying their milieu was deliberate, not an unintended consequence of bombing factories. In November 1940 a memorandum on bombing policy, almost certainly penned by Harris, asked whether the time had not come to strike in full force “against the people themselves.” In May 1941 the director of Air Intelligence welcomed an attack on “the livelihood, the homes, the cooking, heating, lighting and family life of that section of the population which, in any country, is least mobile and most vulnerable to a general air attack—the working class.” The chiefs of staff in June finally endorsed morale attacks that induced “fear of death and mutilation.”88 The idea of collateral damage had been turned on its head: instead of the death of workers and the destruction of their housing being a side effect of hitting factories, damage to factories was a collateral effect of destroying working-class neighborhoods.

The proportion of incendiaries carried by German bombers was known to vary between 30 and 60 percent, concentrated in the first attack groups, while RAF bombers carried between 15 and 30 percent, diluted throughout the force. The critical problem was how to drop enough incendiaries to create fires that ran out of control, which meant smothering an area with firebombs. The attack on the City of London on December 29, 1940, was used as the model. The raid started twenty-eight conflagrations, fifty-one serious fires, 101 medium fires, and 1,286 small ones, and it was this level of assault that could be expected to overwhelm the emergency services.92 Detailed evidence from Britain’s other blitzed cities suggested that incendiary bombs had five times the destructive potential of heavy explosive per ton. They were best used, it was suggested by Air Intelligence, against cities with narrow streets and wooden structures. Germany’s old town centers were “ideal targets for large-scale incendiary attack” because German urban areas were denser and taller than their British equivalents. A salvo of 30,000 British four-pound incendiaries dropped in twenty minutes was regarded as a necessary minimum, though much larger quantities were found to be necessary later on. High explosive was needed to reduce the water supply and ventilate the buildings.

It was realized in the Air Ministry by the summer of 1941 that to maximize the effect of firebomb attack the equivalent of the German Kampfgruppe 100 was required, skilled in navigation so that it could carry out a fire-raising attack that the following bombers could use for their own navigation.94 Portal used Kampfgruppe 100 as his example when he suggested in August 1941 to the government scientific adviser, Sir Henry Tizard, the need to move to a target-marking system as soon as possible.

Pathfinding and target designation

The one lesson that the RAF and the government failed to learn from the German experience was, paradoxically, the reality of relative failure. German bombing did not dislocate the economy seriously, nor did it undermine civilian commitment to the war effort, as the Air Ministry could clearly see. Calculations were made which showed that potential output in the British economy was reduced by no more than 5 percent; even in cities heavily bombed, economic activity was restored to previous levels in between three and eight days.110 It was also difficult to argue that German “morale” would somehow crack if British morale had remained intact after nine months of remorseless assault. When the new directive was shown to the American chiefs of staff at the Argentia meeting between Churchill and Roosevelt in August 1941, they found it hard to reconcile the morale bombing of Germany with the “valorous experience” of the British people under German bombardment.111 The RAF could not ignore this paradox. It was resolved by suggesting that the Germans lacked the qualities of endurance and pluck displayed by the British under fire. The general prejudice among senior airmen was that the German people, as one intelligence report put it, “will not stand a quarter of the bombing” dished out to Britain, though there were few sensible grounds for believing it.112 A report in July 1941, following a meeting in Lisbon with American diplomatic personnel from Germany, suggested that the average Ger...

Lindemann instructed a young economist on his staff in the Statistical Section, David Bensusan-Butt, to examine 650 photographs taken from 100 raids between June 2 and July 25, 1941. The report was ready by August 18. The analysis showed that in general only one in five of all bomber aircraft sent on a mission reached within five miles of the assigned target; of those recorded as actually bombing, the proportion was one in four over Germany, one in ten over the Ruhr industrial area, and on moonless or hazy nights one in fifteen.126 Churchill was alarmed by the revelations: “It is an awful thought,” he wrote to Portal, “that perhaps three-quarters of our bombs go astray.”127 The RAF response was, not surprisingly, defensive. Portal pointed out that weather over Germany had been very poor in June and July; that the Butt Report covered only one-tenth of Bomber Command sorties; that inexperienced navigators probably took images too long after the release of the bombs (almost certainly the case, given the difficulty of operating the camera and seeing the bomb burst below); and, above all, that German raids tracked over Britain showed only 24 percent of German bombers reaching the target area. Even Lindemann admitted that conditions had not been ideal for photographic analysis in the summer months.128 Portal was no doubt correct to argue that the Butt Report was subject to substantial methodological flaws, but the RAF’s own operational evidence gathered since 1940 had consistent...

somehow missed at first the references to the "Butt Report"

The 250- and 500-pound General Purpose bombs were still extensively in use in 1941; larger 1,000-, 2,000-, and 4,000-pound bombs, more suitable for the larger bomber models, were developed during the Blitz and brought into use in small numbers. These Medium Capacity (MC) and High Capacity (HC) bombs had a higher charge-to-weight ratio, a thinner metal shell, and a much greater blast effect. However, they still lacked aluminized explosive, which would have increased that effect more than threefold; only later in the war was Lindemann finally able to persuade the RAF to adopt it. The 4-pound incendiary bomb remained standard equipment but was supplemented by the larger 30-pound firebomb with a blend of phosphorus, rubber, and benzol gel, 400,000 of which were ordered in June 1941 and 3 million used by the end of the war.138 All these bombs became available in quantities too large for the existing bomber force to use. In April 1941, 12 million incendiaries were ordered for the rest of the year and 36 million for 1942; because of magnesium shortages, however, output was only 2.2 million in the nine months of 1941 and 11.8 million in 1942, but these figures were more than enough for a force not yet converted fully to mass incendiary bombing. By the end of 1941 there was a surplus of more than 2 million bombs, and monthly production was double monthly expenditure.139 By the summer of 1941 around 11,000 tons of high-explosive bombs were being produced and filled every month, thou...

Night attacks meant that antiaircraft fire, without radar assistance, was effectively blind. The decentralized pattern of British raiding made it difficult to know what to protect. German air observation posts were set up around fifteen to twenty kilometers from predicted target areas, but nighttime conditions reduced the prospect of accurate information. The numerous sound detectors used in conjunction with searchlights were found to be vulnerable to the British tactic of throttling back the engines to dampen the noise as aircraft approached a potential danger zone. (British crews also believed that throwing empty milk bottles or beer bottles out of their aircraft confused enemy equipment. The “whistling bottle” was said to interfere with sound location and trigger the searchlights to switch off.)148 For the German side a concerted defense was difficult to mount, because RAF bombers failed to damage essential war-economic targets, which were guarded by “air defense strongpoints,” and instead scattered their loads over an extended area with few evident objectives. The Butt Report could essentially have been written by the Germans months earlier.

This was the start of Churchill’s growing disillusionment with what bombing could deliver. His initial enthusiasm had been based on a very limited understanding of what bombers were currently capable of achieving. As a politician he was interested in the prospect that air attack might provoke a political reaction in Germany, but the erratic intelligence available suggested that bombing had done very little to undermine German war willingness, while the clearer evidence nearer home showed that the British political system and social structure had survived intact. Morale was now viewed by the RAF less as a means of political pressure, more as a war of economic and social attrition, or, as Portal put it, “interference with all that goes to make up the general activity of a community.” But to Churchill, who had imagined a more immediate and politically significant effect from bombing, the idea of long-term and unpredictable attrition was an unexciting prospect.

Unlike the RAF, which had never embraced a serious counterforce strategy, the American planners—like the German Air Force in 1940—assumed that enemy airpower would be an essential intermediate target, whose destruction would make the obliteration of the primary objectives possible.173 Morale was not considered a useful target and was not included on the list. Again unlike the RAF, the American planners did not argue about the legality of bombing urban targets or hitting civilians.174 The German economic web, with its vital centers, was treated as an abstraction; the metaphor of the “social body” created a language that distanced those planning the bombing from the reality of civilian deaths.

On May 8, following the Rostock raids, Baker’s deputy, Sydney Bufton, also wrote to Harris with the evidence from plotted photographs that his attacks on Essen in March and again in April showed that 90 percent of bombs had fallen from between 5 and 100 miles from the Essen aiming point. Plots of twelve raids on Essen between March and June 1942 showed that in seven of them fewer than 5 percent of aircraft got within 3 miles. The raids on Rostock, which was easier to locate, being near the coast, showed that 78 percent of the photographs taken were not of the town.205

The arguments over developing a target-finding force equivalent to the German Kampfgruppe 100 had begun in 1941 but were still unresolved when Harris took over. He was opposed to the idea of using the introduction of Gee as an opportunity to develop specialized units to find, identify, and illuminate a target city. Together with other senior commanders, he thought the creation of an elite corps would leave poorer-quality crews to follow behind and would sap the morale of the rest of the force. He favored keeping “lead crews” in each bomber group to find and mark the target, and was impervious to the evidence that this practice failed to produce a concentration of bombing effort. At a meeting with group commanders and the Directorate of Bomber Operations in mid-March, Harris made it clear that he entirely rejected the idea of a target force and was supported by all five group commanders.209 The argument highlighted the extent to which the individual commanders in chief and their subordinate commanders enjoyed independence from the air staff at the ministry in the way they chose to run their campaigns.

In March, Bufton sent out a questionnaire to squadron and station commanders in Bomber Command asking them whether they approved the creation of a target-finding force. The replies were unanimously in favor. A squadron commander based at Oakington, near Cambridge, told Bufton that the senior officers’ First World War experience was valueless in the new conflict: “The crocks . . . must be swept from the board.”

There was also no effective way of measuring what impact the bombing was having on the German economy, military machine, and popular morale. During 1942 the command dropped 37,192 tons of bombs on German soil, compared with 22,996 in 1941, but most of these bombs failed to hit the target area, and the raids cost some 2,716 bombers lost on operations or through accident.235 The first scientific analysis of a major raid was supplied in November 1942 by division RE8 of the Research and Experiments Department, which used British models to calculate the likely degree of homelessness, lost man-months, and financial cost of the 1,000-bomber raid on Cologne six months before. The first statistical assessments of acreage destroyed and of the ratio between high-explosive and incendiary damage were only ready in January 1943.236 Until then, claims that cities had been wiped out or obliterated were mere guesswork. In fact, during 1942 the damage to the German economy and society remained limited. A small number of spectacular raids in the late spring had not been sustained, and the German civil defense and repair organization coped with the consequences with little pressure. The German economy cushioned the bombing and expanded weapons output by more than 50 percent during the year. Postwar calculations in the United States Bombing Survey suggested a loss of potential overall production of 2.5 percent due to British bombing, or roughly half the impact of the German Blitz on Britain. D...

The pressure on airfield space was reduced by the decision very early in the war to disperse most of the basic training overseas. It is seldom sufficiently acknowledged that the British bombing effort during the war was in reality a British Commonwealth undertaking. Britain was never “alone” during the Second World War. On December 17, 1939, an agreement had been signed with the Canadian government to set up the British Commonwealth Air Training Scheme on bases in Canada. During the course of the war a peak of seventy-three schools were set up under the scheme, with a further twenty-four under RAF control. The scheme turned out 131,000 trained aircrew, including 49,808 pilots and 29,963 navigators. By 1944 over 3,000 completed training each month. The majority (55 percent) went into the Royal Canadian Air Force (a high proportion for Canadian units in Bomber Command), while the RAF took one-third; the remainder went to the Australian and New Zealand air forces.51 Other British aircrew were also posted to training schools in the United States under the so-called Arnold Scheme. In April 1941 the American army agreed to allow British participation in the Southeast Air Corps Training Program in the southern United States, and 7,885 pilots were sent for basic training, together with 1,200 navigators. The program was linked with Canadian training, but the failure rate in the United States was high because of the poor level of scientific education among British recruits, and the ...

On the night of May 16–17, under the code name Operation Chastise, nineteen Lancasters were dispatched, of which twelve attacked the three dams, breaching the Möhne and the Eder, but doing only superficial damage to the Sorpe. Two-thirds of the water escaped from the reservoirs and 1,294 people were drowned in the inundation, including 493 foreign workers. The destroyed dams lost an estimated 25,000–30,000 tons of masonry, but both were repaired by October, while the long-term damage to the industrial water supply was less than had been hoped.91 Further attacks were ruled out, partly because of the high loss rate. Only eight Lancasters returned from the raid and 56 out of the 113 aircrew were lost.

None of these efforts at calculating what Bomber Command was achieving were coordinated or consistent. Nor could they confirm whether bombing was a strategically sensible use of British resources.

What resulted in a series of raids appositely titled Operation Gomorrah was the single largest loss of civilian life in one city throughout the whole European war, exceeded only by the 250,000 Japanese killed in the firebombing of Tokyo and the atomic attacks on Hiroshima and Nagasaki. The destruction of Hamburg in an uncontrollable firestorm on the night of July 27–28, 1943, is often presented as if it were an accident, the result of exceptional meteorological conditions and the failure of German defenses, and not a product of deliberate intention. This is to misunderstand entirely the purpose of the city-bombing campaign, which was predicated from the start on causing as much general damage and loss of life as possible by means of large-scale fires. The firebombing of Hamburg was not exceptional. Not for nothing was its vulnerability rated “outstanding”; it was expected to burn well.