by Andrew Brown
Although the Tizard Committee was immediately reconstituted, with Sir Edward Appleton taking Lindemman’s place, and succeeded in integrating radar defence into Fighter Command, a bitter legacy remained between Lindemann and Tizard. In addition to the many coincidences already noted, both men were almost blind in one eye. Lindemann became a pilot after instantly memorizing the letters on the vision-testing chart and fooling the examiner; Tizard simply asked for permission to wear glasses under his flying goggles. Their outlooks on life were very different: Lindemann possessed a grasp of power politics that Tizard found distasteful. Tizard had a common touch and collegial manner that Lindemann completely lacked. Their inability to work together, apparent so soon in committee, would have major repercussions during the war to come.
At the outbreak of war, Churchill immediately installed Lindemann and a team of statisticians and economists at the Admiralty to supply him with data on all aspects of shipping and to scrutinize all the departmental papers that were circulated to the War Cabinet. Churchill used Lindemann’s group to present him with a continuous stream of information on the war effort – he preferred it to be in diagram or chart form and any numbers had to be interpreted by Lindemann. The Prof was a member of his closest circle and, as Churchill explained to Lord Gort, the Commander-in-Chief of the British Expeditionary Force in 1940, ‘in all my secrets’.14 Churchill later gave a revealing assessment of his wartime relationship with Lindemann: ‘There were no doubt greater scientists than Frederick Lindemann, although his credentials and genius command respect. But he had two qualifications of vital consequence to me. First… he was my trusted friend and confidant of twenty years. Together we had watched the advance and onset of world disaster. Together we had done our best to sound the alarm. And now we were in it, and I had the power to guide and arm our effort. How could I have the knowledge? Here came the second of his qualities. Lindemann could decipher the signals from the experts on the far horizons and explain to me in lucid, homely terms what the issues were.’15
Hard-working and productive though Lindemann’s statistical department was, the cream of Britain’s statisticians in 1940 were working on civil defence research at Princes Risborough, where they had been brought by Stradling and Bernal. They included Bradford Hill, the medical statistician from the London School of Hygiene and Tropical Medicine and Frank Yates, who had carried out important studies of crop production at the Rothamsted Experimental Station. Bernal may have met Yates through his plant virus work with Pirie and Bawden, and he subsequently introduced him to Zuckerman, starting an important collaboration on the quantification of bomb damage.
Less illustrious than Bradford Hill or Yates was Dr F. Garwood, and it was with him that Bernal worked on a remarkable theoretical exercise in the spring of 1940. Their intention was to make a realistic assessment of the damage that would result from an intensive air raid on a city. We have seen how Churchill in 1934 predicted tens of thousands of deaths in London from a week of bombing, and if anything, government estimates in the intervening years had become more apocalyptic. The basis for these calculations rested on the limited experience of German bombing in World War One, when about 300 tons of bombs had produced almost 5,000 casualties, of which about one third were fatal. The casualty rate in two daylight raids on London had been high, and the Air Staff assumed a casualty rate of about 50 per ton of bombs dropped on a city. In 1938, the Committee of Imperial Defence predicted that the Luftwaffe could maintain a daily rate of 600 tons on London alone and the Ministry of Health were projecting 600,000 deaths and twice that number wounded in the first six months of such a campaign.16 These dire predictions took no account of the details of any raid, nor of any protection from shelters, and were crude linear extrapolations from meagre World War One data.
Bernal and Garwood set out to make a more realistic analysis and for verisimilitude chose the city of Coventry as ‘an attractive target on account of its numerous aircraft factories’.17 They worked from Ordnance Survey Maps and marked points on the maps where bombs might fall, and then assessed the likely damage and casualties from the explosion of 250 kg bombs. Bernal thought that even if Coventry were targeted because of its aircraft and engineering factories, Luftwaffe pilots would need an unmistakable aiming point. The analysis was run with two different bull’s-eyes: Coventry Cathedral and the Humber car factory about one mile from the Cathedral. He and Garwood also allowed for probable error by drawing circles of different radii (one mile and 1/2-mile) to define areas in which there was a 50% chance of a bomb falling, when it was aimed at a conspicuous landmark at the centre. In this way they were able to build up spatial distributions of the bombs dropped on the city. The number of casualties caused by each bomb was then estimated, assuming people to be in their houses or in Anderson shelters or in factories, where they might be unsheltered or in trenches. Exact figures for total and factory populations were unavailable so Bernal and Garwood made estimates depending on whether the raid took place in daylight or at night. They ran their statistical model for different-sized raids (500 or 1,000 bombs), with two different aiming points, and for sheltered and unsheltered populations, with location varying depending on day or night attack. This was a much more meticulous analysis than any previously attempted and showed that ‘the great majority of bombs do no damage at all, but that the greatest number of casualties are produced by direct hits on single shelters’.18 For a one-thousand-bomb raid, the number of predicted casualties varied between 630 (at night with everyone sheltered) and 7,350 (daytime raid with no one sheltered). It appeared to them that ‘in industrial towns a great saving of life could be brought about by improving the standard of factory shelter’.19
Bernal and Garwood’s report appeared in June 1940 at a time before there had been any heavy bombing of British (or German) cities. On the night of 14th November, Coventry suffered the heaviest raid on any British city to date and the bombing was particularly destructive because the Luftwaffe were guided by X-gerät, a radio navigational aid which was accurate to about 100 yards at a range of up to 200 miles.20 Bernal’s assumption that the Cathedral would be the aiming point seems correct in that it was completely destroyed, and it is estimated that 500 tons of high explosive (HE) plus incendiary bombs were dropped during the night-long attack. More than five hundred people were killed, out of total casualties of just under two thousand. This was about twice the quantity of HE bombs used by Bernal and Garwood in their model, and if one doubles their estimates to reflect this, their closest figure of 2,260 casualties was based on a night raid, where the population took shelter and the probable error in dropping the bombs on the Cathedral was one mile. Even in what Churchill described as ‘the most devastating raid which we sustained’21 the casualty rate was about four per ton in comparison to the pre-war estimate of fifty per ton, and ‘the all-important aero-engine and machine-tool factories were not brought to a standstill; nor was the population, hitherto untried in the ordeal of bombing, put out of action. In less than a week an emergency reconstruction committee did wonderful work in restoring the life of the city.’22
Once the German bombing started in earnest, it became clear to Bernal that the type of evidence that he and Zuckerman had collected on a sporadic basis needed to be compiled more systematically in order to build an accurate picture of the damage being caused. Zuckerman took the lead in establishing a Casualty Survey, which had its London headquarters at Guy’s Hospital. Most of the surveyors were young women like Renée Brittan, a student at Birkbeck College, who was recruited for the work by Brenda Ryerson and Bernal. Birkbeck had reopened for classes at weekends (instead of nights), and Renée fitted in the bomb survey work with her studies. She wandered around small streets ‘in Bermondsey and Southwark, particularly in Bermondsey docklands and got a list of the “incidents” that happened the previous night. We went around the sites of the “incidents” as they were known, and measured the bomb holes, and drew maps of the surrounding physical damage and interviewed as many people as we could
who had been involved, and took the information back to Guy’s where we did our homework. Then I went home and did Birkbeck homework, which was due before the weekend lectures and started work again on Monday.’ After collecting figures from the health department of the local Bermondsey Council on the dead and injured, she tried to plot the places where the casualties occurred: ‘It was a mapping job: people, places, effects and of course the size of the bomb – a 25 pounder or a 50 pounder, no 25 kilos or 50 kilos – it was my first introduction to kilos I think.’23
The information collected and plotted by Renée and other field workers was sent to Oxford for analysis. Zuckerman wanted to know whether his experimental estimates about the effects of direct blast were valid and would give a reasonable estimate of what to expect in the field; he also wanted to find out to what extent bomb splinters or small fragments caused serious injuries to people during air raids. Frank Yates, the statistician introduced to the work by Bernal, quickly saw that the types of observations that Zuckerman had been making could be generalized into ‘standardized casualty rates’ that could be adjusted for the proportion of the population in shelters or in the open. As a result, Zuckerman was able to write a report on air-raid casualties that became ‘the standard work on the subject’.24
Margaret Gardiner moved from her tiny cottage in Maidensgrove to a slightly bigger one in the Buckinghamshire village of Fingest. The arrangement suited Sage admirably since it was close to both Princes Risborough and the headquarters of Bomber Command in High Wycombe, where he was spending an increasing amount of time. His life was organized as much as it could be by another capable young woman Kathleen Watkins. She was a graduate and a Wren, who had been appointed as assistant secretary to the Civil Defence Research Committee in July 1940. After committee meetings, Sage always seemed to leave some of his belongings behind and it became her task to return them to him. He then would ask her to take some dictation for him and soon she became his personal assistant, working at Princes Risborough. Dictation proved a challenge because he would often not bother to finish one sentence before rushing on to the next. Miss Watkins subsequently wrote a guide for future secretaries, assuring them that there was ‘no need to be afraid of him although many are. In spite of all appearances to the contrary, he is really good-tempered, kind-hearted and exceptionally reasonable. He expects you not so much to do what he tells you to do as to do what he meant to tell you to do, or what he would have told you to do if he’d thought it out more carefully. Do not mistake impatience for ill-humour; his time estimates are usually between 33–50% of time required (applies to his own work as well).’25
Margaret’s son, Martin, now ‘a most ill-disciplined small boy’ according to one acquaintance, adored having regular visits from his father. Kathleen Watkins was struck by the likeness of father and son. She used to bicycle to Fingest on Sunday evenings to deliver papers to Sage for him to take up to London the next day. One summer’s evening she arrived at the cottage, which appeared deserted. She called out and went upstairs to find Sage in bed with Martin reading How the Leopard Got his Spots – their faces looked identical.26
Bernal and Zuckerman’s bomb survey findings were noticed at the highest level, and although the research was initially motivated by a desire to improve civil defence, their results were seen to have immediate application in weapon design. Churchill sent the following note to the Secretary of State for Air on 16th July 1941: ‘Investigations by the Ministry of Home Security into the effect of German high-explosive bombs has shown that a far greater amount of damage is done by blast, which destroys building, etc., than by splinters, which find very few useful targets, especially at night, when most people are under cover. The higher the proportion of high explosive to bomb-case the greater the blast. If the weight of the metal case is increased we get more splinters. Our general purpose bombs have a charge-weight ratio of about 30–70. The Germans work with a larger ratio, about 50–50. These are not only more efficient for destroying cities; they are also cheaper.’27 Churchill had a renewed interest in the effects of bombing because the Soviet Union had been invaded by the German army the previous month and, as he wrote to ‘Monsieur Stalin’, the RAF would continue to bomb German towns heavily ‘to force Hitler to bring back some of his air-power to the West and gradually take some of the strain off you’.28
Like all British communists, Sage rejoiced at having the Soviets as anti-fascist allies after their period of appeasement. He was an enthusiastic contributor to a two-day symposium on ‘Science and Marxist philosophy’ held in London in August 1941. His account of the meeting was published in Nature, and was followed three weeks later by his review of present-day science and technology in the USSR. In this second article, Sage returned to a familiar theme of planning science to meet the needs of society, something which he thought the Soviets had been doing successfully for twenty years and which the British were finding difficult to manage even in wartime. He hoped that ‘fighting together in a common cause, scientific workers in Great Britain will come to understand, far better than from any description, the new spirit and method which characterize science in the USSR, and that, in turn, we may be able to provide some of the advantages of a long tradition of discovery and criticism. The new world for which we are all fighting and working will need every contribution that science can bring.’29
After some heavy losses on daylight bombing raids, the RAF had confined itself to night flights over Germany from the spring of 1940. The primary objectives had been to bomb oil installations and aircraft factories, but with the continuing Blitz of London and other British cities, it was made clear in a series of directives to Bomber Command that incendiary bombing of areas surrounding the primary targets was encouraged to undermine German morale: thus began the area bombing of industrial German cities.30 By the start of 1941, Bomber Command was steadily losing crews and planes, with no indication that their sacrifice was bringing about any worthwhile damage to the German war machine. The RAF remained, however, the only force that could attack the enemy, which was still trying to strangle Great Britain. Early in 1941, Sage became officially attached to Bomber Command in order to assist in the assessment of its operational performance. He spent most of his time in the photographic room, where the results of raids were charted, and quickly became aware that the accuracy of bombing at night, after journeys of several hundred miles with uncertain navigation in unpredictable winds and weather, was lamentable. This was well understood by the flight crews themselves. One pilot said to him: ‘You can think it damn lucky, old boy, that we drop the bombs in the right country.’31
A senior officer at High Wycombe told Bernal that ‘Bomber Command is not concerned with the results of bombing’32 as long as their planes flew over Germany and as many as possible got back. But at the ‘lowly level’ of the photographic room, the Canadian officer in charge was ‘unaccountably interested in the actual conduct of the war with the Germans rather than inter-service and inter-command politics’.33 Sage promised him that he would see what he could do to improve matters, and the next time he spoke to Lindemann, he mentioned the unsatisfactory state of affairs at Bomber Command. Lindemann’s response was dismissive – he was a regular visitor to High Wycombe on his journeys between Oxford and London, and received a steady supply of photographs showing the successes of the Bomber Command. Sage knew about this, because every time Lindemann came, he arrived with great ceremony in his Ministerial limousine and was received at the front entrance by the Air Marshal. There was also a standing instruction that ‘Whenever a photograph could be obtained in which a British bomb could be seen exploding on any kind of target in Germany, it was blown up and sent to the PM.’34 When this was explained to Lindemann, his initial reaction was one of ‘blank incredulity’, but Bernal insisted that he was being given a biased impression, and after repeated pleading, the Prof agreed to visit High Wycombe incognito.
So it was that the Prof and Sage drove from Princes Risborough in the latter’s 1938 Austin 10 to ‘a
postern at the back’ of the HQ from where they could make their way, unannounced, to the photographic room. Once the Prof saw the unglossed evidence, ‘he was immediately convinced and horrified’. He turned to Bernal and said: ‘You realize that I have not seen anything.’ Sage replied diplomatically that he quite understood and thought that Lindemann would find the right way to deal with the situation. The consequence was that at the next meeting of the Air Council, the Prof, ‘with characteristic suavity’ congratulated Bomber Command on its performance, but recommended that a little more statistical analysis should be performed. He went on to propose that, Mr David Butt, an economist from his ‘circus’, should be seconded to Bomber Command for this purpose.35
Butt soon set about analysing photographs from one hundred different raids to determine the accuracy of RAF bombing around the stated aiming points. His results were available within weeks, and represented a stunning indictment of the existing bombing programme. Butt concentrated on the two-thirds of returning air-crews, who claimed to have reached their targets, and found that in fact only about one third of them came within a radius of five miles of the aiming point. In raids on the Ruhr valley, which was always covered by industrial haze, the proportion fell to one-in-ten. On moonless nights or in the face of active German fighter planes, the figures were even worse. Butt’s sobering conclusions were met with disbelief by some in the higher reaches of Bomber Command; they were a complete repudiation of the idea of precision bombing.
The Butt Report would prove a major stimulus to the introduction of new navigational aids and the Pathfinder squadrons; it made a deep impression on Churchill, who now realized that the claims made by Bomber Command were exaggerated. His memorandum to the Chief of the Air Staff, dated 7th October 1941, while expressing hope that ‘the air offensive against Germany will realise the expectations of the Air Staff’ warned against ‘placing unbounded confidence in this means of attack’.36 He cautioned that even ‘if all the towns of Germany were rendered largely uninhabitable it does not follow that the military control would be weakened or even that war industry could not be carried on… It may well be that German morale will crack, and that our bombing will play a very important part in bringing the result about. But all things are always on the move simultaneously, and it is quite possible that the Nazi war-making power in 1943 will be so widely spread throughout Europe as to be to a large extent independent of the actual buildings in the homeland.’ The memorandum mildly admonished the Air Staff for its pre-war assessments of the destruction that would be wrought by air raids, the prospect of which paralysed statesmen of the day, contributed to the desertion of Czechoslovakia in 1938 and ‘after the war had begun, taught us sedulously to believe that if the enemy acquired the Low Countries, to say nothing of France, our position would be impossible owing to the air attacks’. In this penetrating note, Churchill was thinking subtly about complex issues and reached, what with hindsight, appears to be a balanced position. It also demonstrated that he had assimilated Bernal and Zuckerman’s major findings, no doubt with the benefit of Lindemann’s explanation, as well as the Butt Report.