by Andrew Brown
Before the war, Bernal and Lindemann had known each other by reputation, an arrangement more likely to produce mutual repulsion than attraction. It is possible that they might have crossed paths at the country house of Lord Melchett, who was friendly with both men, but their first recorded meeting was when the Prof came as a guest, with Melchett, to a Tots and Quots dinner in March 1940. Zuckerman’s minutes of the occasion recorded Sage as making his characteristic plea for the effective planning of science, when the Prof intervened to point out that the war first had to be won before the future of science could be considered – the minutes do not record whether the Prof’s remark was delivered with his characteristic sneer.37 Undaunted, Sage replied that unless the role of scientist was greatly expanded, the war would not be won. Zuckerman, a more emollient and flexible character than Bernal, contented himself with the observation that ‘the Prof could always be relied upon to stir dissent, even when he stated the obvious’.38
Zuckerman knew the Prof well – they were both Fellows of Christ Church, Oxford and often conversed in the Common Room after dinner. They met there one evening late in August 1941 and naturally talked about the progress of the war. It did not take long for the subject of bombing to come up, since Zuckerman was in the midst of analysing the data collected by the Casualty Survey and was writing papers on blast injury and the wounding mechanism of high-velocity missiles. Lindemann, who had been given a barony in June, was now Lord Cherwell of Oxford. He had just returned from Newfoundland with Churchill on the battleship Prince of Wales after the first meeting with President Roosevelt. One of the first documents Cherwell received on his return to London was the Butt Report, and its unhappy findings were at the forefront of his mind as he talked to Zuckerman. While not disclosing the contents of the report to Zuckerman, Cherwell was ‘much concerned about the hostile reaction in official and unofficial quarters to our bomber offensive’.39 There was a growing feeling in the face of the shipping losses to U-boats in the North Atlantic that Bomber Command’s attention should be turned to anti-submarine measures and more new planes should be diverted to Coastal Command. Cherwell thought that it would be a mistake to ease up on the offensive against the German homeland, since it was possible that the performance of Bomber Command could be improved, and he asked about ways of assessing the overall damage done in heavy raids.
Zuckerman thought that some measure of what could be achieved ‘as a result of a “unit attack” of, say, a thousand tons of bombs against a German city by deriving a corresponding measure from German attacks against selected British cities’.40 The cities he had in mind were Birmingham (an engineering and munitions center) and Hull (a port). The Ministry of Home Security had initiated a Bomb Census in 1940 so that a record was made of every bomb dropped on the United Kingdom, with estimates by local observers of the resulting damage and casualties. Zuckerman knew from Bernal that the bomb tallies were accurate for Birmingham and Hull. Cherwell told Zuckerman that he was interested in such questions as ‘how many tons of bombs does it take to break a town’ and ‘how should the bombs be delivered – should it be in one sharp attack, or in what ratios should the total load be distributed and over how many nights’.41
The request to survey Birmingham and Hull soon arrived at Princes Risborough. Stradling selected Bernal and Zuckerman to carry out the work, with Zuckerman in charge of casualty and social aspects, and Sage in charge of everything else. Two teams of about forty members each were assembled over the next two months, and they mounted the most detailed day-to-day analysis of the economies and wartime stresses of the two cities, recording ‘everything in great detail from the number of pints drunk to the number of aspirins bought’.42 There were three major raids on Birmingham between June 1940 and July 1941, while Hull experienced four in the shorter period March to November 1941. The Bomb Census showed that for an area with a radius of about twenty miles around Hull, a total of 960 tons of bombs were dropped, of which one third fell within five miles of the city centre. To study the effects on the cities’ populations and general way of life, seven thousand questionnaires were completed and analysed. Several thousand essays were collected from schoolchildren, giving their impressions of life in the air raid shelters, and how the bombings affected them and their families. Production figures for over six hundred factories were obtained for the periods in question, and detailed structural studies were made for some one hundred factories, mills and storehouses.
Results began to emerge early in 1942 and a short final report was delivered on 8th April.43 At the centres of the cities the calculated density of high explosive (HE) bombs was forty tons per square mile, and at that intensity there was no evidence of breakdown of morale: ‘In neither town was there any evidence of panic resulting from a series of raids or from a single raid.’44 The destruction of homes (typically by HE bombs and not by fire) caused the most public distress, and thirty-five people were de-housed for every one killed. But a large city like Birmingham could absorb the bombed-out population easily, and temporary evacuation did little to disrupt work patterns. When it came to the local economy, it was found that the direct loss of production in Birmingham due to raids was only about five per cent. What losses there were resulted almost entirely from direct damage to factories, which in distinction to dwellings, proved very susceptible to fire. Crucial machine tools were extensively damaged by fire (which in most cases could have been prevented by adequate water supplies and better fire services), but overall only two per cent of factories were seriously damaged by high explosive. Transportation was only interrupted temporarily in the absence of continuous attacks. In conclusion, the authors wrote that they were not yet in a position ‘to state what intensity of raiding would result in the complete breakdown of the life and work of a town, but it is probably of the order of 5 times greater than any that has been experienced in this country up till now’.45
Bernal’s pocket diary46 for 1942 shows that he had multiple meetings early in the year with the three protagonists in what became the most infamous dispute involving WW II scientists. In its first iteration, it was essentially an argument about Bomber Command’s operational performance, although there were also personal differences adding some acidity to the mix. Two decades later with two of the principals dead, the debate was revived by C.P. Snow, essentially as a morality play. On both occasions, Bernal was a peripheral figure, but his role was influential.
On 29th January, Sage had lunch with Lord Cherwell. Despite the recent entry of the United States, the war was going badly with the Japanese overrunning South-East Asia, and Rommel’s tank forces rampant in the desert of North Africa. Churchill that day wound up a three-day Vote of Confidence debate, in which he had warned the House that ‘worse is to come’.47 There is no record of the conversation between Bernal and Cherwell, but the lunch would have been at the latter’s behest, and the main reason surely was to glean information from the surveys of Birmingham and Hull. On 10th and 13th of February, Sage had meetings with Tizard, who was still prominent as an unofficial scientific adviser to the government and service chiefs, although operating always in Cherwell’s shadow. Bernal gave Tizard a summary paper on the Birmingham and Hull surveys, which Tizard noted as showing, on the whole, that ‘the effect on production and morale has been surprisingly small’.48 The week after his meetings with Bernal, Tizard wrote to the Secretary of State for Air stating that ‘the present policy of bombing Germany is wrong’ and much the same effect of tying up German resources on home defence ‘could be achieved by steady bombing on a much smaller scale than is at present contemplated by the Air Staff’.49 Tizard thought that far more effort should be put into using long-range bombers to attack the German U-boats and to protect North Atlantic convoys. At the same time, Tizard wrote to the Deputy Chief of the Air Staff pointing out that during the previous nine months Bomber Command had lost more than seven hundred planes and, with them, probably as many crew members as Germans killed by the bombs dropped. The Air Marshal’s immediate reaction was t
hat Tizard had ‘been seeing too much of Professor Blackett… [who was, in turn,] biting the hand that fed him’.50
The Bernal diary shows that he had been seeing plenty of Professor Blackett, newly appointed as the Admiralty’s Chief Adviser on Operational Research, having already pioneered operational research (OR) in the Anti-Aircraft and Coastal Commands. Blackett was a Navy man, having served as a gunnery officer and then lieutenant in World War One; he held to the ethical principle that wars should be fought between opposing armed forces and that the enemy’s civilian population should not be made a deliberate target.51 In early 1942, he made his own estimates of the casualties that Bomber Command were likely to be inflicting on German citizens. The method he chose was to base his calculations on the known effectiveness of German bombing of England between August 1940 to June 1941, and after making allowances for bomb types and navigational errors to project the outcome of the RAF bombing raids for 1941. His estimate of 400 civilian deaths per month was shown to be remarkably accurate after the war,52 and it seems very probable that he would have discussed his calculations with Bernal (and to have relied on him for data on bomb detonation and tonnage dropped on Britain). Whatever degree of collaboration there was between Sage and Blackett, they both delivered their notes to Tizard at the same time.
Aside from his briefing by Bernal in January, Cherwell was also being fed information by Zuckerman, who received a letter from D.M. Butt, dated 24th February, saying ‘Lord Cherwell has quoted in conversation some figures you gave him relating air-raid casualties to the tonnage of bombs and the density of housing, and has asked me to do certain calculations which involve them. He did not seem, however, entirely clear about the definitions and… you could perhaps let me have a note of them. What I am particularly anxious to get is the casualties per ton in areas with different housing densities.’53 Butt’s letter closed with the assurance that ‘We do not want to anticipate any results of the Birmingham–Hull survey, but these figures are rather essential to an argument on quite different matters.’
Butt was plainly doing his master’s bidding, and because he did not know why the Ministry of Home Security survey was commissioned in the first place, the study he was now working on must have seemed quite different to the survey. Lord Cherwell, however, was pursuing his original intention of assembling evidence to support the devastation of Germany from the air. Cherwell started to construct his own argument from the Hull–Birmingham statistics, using simple logic (which appealed to the politicians and airforce chiefs) to reach false conclusions. Like any minute to Churchill, Cherwell’s had to be kept to one side of paper and was delivered on 30th March, before circulation to the Defence Committee on 9th April. It read in part:
Careful analysis of the effects of raids on Birmingham, Hull and elsewhere have shown that, on the average, 1 ton of bombs dropped on a built-up area demolishes 20–40 dwellings and turns 100–200 people out of house and home… We know from our experiences that we can count on nearly 14 operational sorties per bomber produced. The average lift of the bombers we are going to produce over the next 15 months will be about 3 tons. It follows that each of the bombers will in its lifetime drop about 40 tons of bombs. If these are dropped on built-up areas they will make 4,000– 8,000 people homeless.
In 1938 over 22 million Germans lived in 58 towns of over 100,000 inhabitants, which, with modern equipment, should be easy to find and hit. Our forecast output of heavy bombers (including Wellingtons) between now and the middle of 1943 is about 10,000. If even half the load of 10,000 bombers were dropped on the built-up areas of these 58 German towns the great majority of their inhabitants (about one-third of the German population) would be turned out of house and home.
Investigation seems to show that having one’s house demolished is most damaging to morale. People seem to mind it more than having their friends or even relatives killed. At Hull signs of strain were evident, although only one-tenth of the houses were demolished. On the above figures we should be able to do ten times as much harm to each of the principal 58 German towns. There seems little doubt that this would break the spirit of the people.54
This statement was regarded by Zuckerman as a misrepresentation, since he and Bernal had concluded that there was no breakdown of morale in either Hull or Birmingham, but Cherwell could have pointed to the following passage in their report:
The situation in Hull has been somewhat obscured… by the occurrence of trekking [people leaving the town at night to take shelter in surrounding countryside], which was made possible by the availability of road transport and which was much publicized as a sign of breaking morale, but which in fact can be fairly regarded as a considered response to the situation. In both towns actual raids were, of course, associated with a degree of alarm and anxiety, which cannot in the circumstances be regarded as abnormal, and which in no instance was sufficient to provoke mass antisocial behaviour.55
While Cherwell was selective in his reading of the Bernal–Zuckerman report, the greatest fallacies in his own minute resulted from false assumptions that were immediately obvious to Tizard and Blackett. Bernal and Zuckerman were not privy to its contents, although it is possible that Bernal learned of them from Blackett. Cherwell’s paramount error in Blackett’s eyes was to assume that all the bombers to be delivered from the factories in the next eighteen months, would, during the same period, drop their full quota of bombs on Germany. As a result, Blackett thought ‘Lord Cherwell’s estimate of what can be achieved is at least six hundred per cent too high.’56
Tizard challenged nearly every statistic given by Cherwell, and told him that ‘the way you put the facts as they appear to you is extremely misleading and may lead to entirely wrong decisions being reached, with a consequent disastrous effect on the war’.57 The Tizard view would be confirmed in the official post-war history, which observed that the policy of area bombing ‘could not be justified by the probability calculations themselves because the calculations seemed probable only to those who, in any case, believed in the policy’.58 At the end of April, Tizard combined his criticisms with Blackett’s in a detailed memorandum to Cherwell and the Air Minister in order to show that ‘a policy of bombing German towns wholesale in order to destroy dwellings cannot have a decisive effect by the middle of 1943’. In an accompanying letter, he also attempted conciliation with Cherwell, saying that he did not ‘really disagree with you fundamentally, but only as a matter of timing… [because] we must preserve command of the seas, and it is difficult for me to see how we are going to do this without strong support of the Navy by long-range bombers’.59
Blackett and Tizard were correct about the shortcomings in Cherwell’s proposal, but they were seeking to be objective and he was not. Tizard knew this and ‘was never prepared to accept any opinion emanating from Cherwell as an honest one’.60 Soon after Churchill became Premier in 1940, Tizard had contributed to a scathing memorandum ‘On the making of technical decisions by HM Government’ deploring Churchill’s exclusive reliance on the Prof for technical advice. In the words of the memorandum:
Professor Lindemann… is completely out of touch with his scientific colleagues. He does not consult with them, he refuses to co-operate or to discuss matters with them, and… his judgement is too often unsound… He has no special knowledge of many of the matters in which he takes a hand… Most serious of all is the fact that he is unable to take criticism or to discuss matters frankly with and easily with those who are intellectually and technically at least his equals.61
Despite all that he had achieved at the Clarendon Laboratory, the Prof was still not accepted by the British scientific community; when he was elevated to the peerage in 1941, Churchill’s private secretary predicted it would ‘cause anger in many quarters and especially at Oxford, but not as much as when it is learned that he proposes to call himself Lord Cherwell of Oxford’.62 On hearing of the title, Tizard’s only comment was ‘the Cherwell is a small and rather muddy stream’.63 But Tizard knew that he could never match
Cherwell in influence once Churchill became Prime Minister, and for all Tizard’s own great contributions, Cherwell had an annoying habit of wrong-footing him. Tizard was not as tough as Cherwell and lacked his visceral hatred of the Germans.
Churchill’s promise of ‘worse is to come’ made at the end of January 1942 was amply fulfilled by March. Singapore had fallen, and the Japanese had invaded Java and Burma; the US Navy proved completely unready to defend its Atlantic coastal waters and U-boats were sinking an increasing tonnage of shipping. Closer to home, the two battle-cruisers Scharnhorst and Gneisenau were able to pass through the English Channel, to the dismay of the British public. Stalin was pressing for an Allied amphibious landing in northern Europe that would create a Second Front to draw German troops away from the Eastern Front. Roosevelt made it clear to Churchill that this would not be practicable for at least two years, and in the meanwhile British Intelligence decrypts of Enigma signals were suggesting a renewed German offensive against Russia in the summer. Under ‘the continuous crushing pressure of events’ as his daughter put it, it was not surprising that Churchill was at a low ebb.64