This was what the Vickers chairman now did. A shouting match followed, in which the designer offered his resignation, and Craven shouted ‘Mutiny!’ They parted on terms of mutual acrimony. Moreover, while Wallis was not often a grudge-bearer, he never forgave AVM Linnell for the part he played in attempting to kill off Upkeep. He went home despondent to Effingham, sincerely determined upon resignation, as was scarcely surprising after the humiliation he had suffered. Craven, whose responsibility was to Vickers, can scarcely be blamed for his behaviour, after being told by the Ministry of Aircraft Production – upon whose goodwill his company depended for orders – that its chiefs were tired of his nagging, insistent assistant chief designer (structures). Why should such people as Linnell, Craven and indeed Harris have accepted at face value the workability of a new weapon which represented a marriage of technologies of extreme sophistication with others of almost childlike simplicity, which when fitted to a Lancaster caused it to resemble a clumsy transport aircraft with an underslung load?
Yet Wallis knew that, whatever Craven said about the MAP’s view of Upkeep, the Admiralty remained enthusiastic about Highball. On 26 February, by previous arrangement he drove to London to attend a meeting that was to be chaired by the now-detested Linnell, to discuss measures to improve the aerodynamics of what some described as ‘the golf mine’ – because of its resemblance to the shape of a golf ball. After Wallis was told that Roy Chadwick of Avro, designer of the Lancaster, would also be attending, he understood that Craven had got things all wrong the previous day: the RAF had not abandoned Upkeep.
When the delayed meeting finally convened at 3 p.m. that Friday, in Linnell’s office at MAP on London’s Millbank, it was to receive tablets from on high. Sir Charles Portal was not only chief of air staff and a former C-in-C of Bomber Command; he had also been among the first enthusiasts for attacking Germany’s dams. He was troubled by doubts about Sir Arthur Harris’s obsession with destroying cities. His reservations were founded not upon moral scruples – no senior wartime airman admitted to those – but instead on uncertainty about its war-winning potential. Portal never summoned the courage to sack Harris, even in the winter of 1944–45, when his subordinate directly defied targeting orders. But the CAS was always at heart a proponent of attacking precision objectives, if means existed to make such a policy work. Now, Barnes Wallis promised to provide these; to make possible fulfilment of the RAF’s 1937–38 dream, of an assault upon Germany’s dams.
The array of brass assembled at the MAP on the afternoon of 26 February 1943 was told that the chief of air staff had given his assent, or rather had issued an order, to proceed with immediate development of Upkeep. Portal wrote: ‘I think this is a good gamble.’ The reaction of Sir Charles Craven, who was also present, is unrecorded. He must have felt privately foolish, if not furious, following his ugly dressing-down of his designer four days earlier. What the CAS demanded, however, Vickers must seek to provide.
Linnell, too, can scarcely have enjoyed announcing – against his own strong personal conviction – the decision to prioritise Upkeep over the Windsor bomber. ‘The requirement for bombs,’ this MAP potentate now said, ‘has been stated as one hundred and fifty to cover trials and operations’ – one hundred and twenty were eventually made. It was further stated that studies of the German dams showed that 26 May – just three months ahead – was the latest date in 1943 on which they could plausibly be attacked. It would thus be necessary to build thirty ‘Provisioning’ Lancasters, as they had been codenamed, and to produce a sufficiency of bombs by 1 May, to provide reasonable time for aircrew training for the operation. The MAP’s budget for research on Upkeep, which in August 1942 had been raised from £2,000 to £10,000, was now further increased to £15,000, and later again on 1 April to a princely £20,000.
While Portal made a personal commitment that enabled Upkeep to be unleashed, it deserves emphasis that he placed a relatively modest bet. Only air-power fantasists could suppose that a single squadron of Lancasters, a maximum of twenty bouncing bombs, would cripple the entire water system of the Ruhr, an aspiration demanding a much larger force even if Wallis’s weapons were half-successful – almost no new weapons system in history has performed better than that. Yet a squadron was all that the Air Ministry would authorise, in the face of Harris’s virulent hostility, a limited supply of aircraft and uncertainty about the viability of Upkeep. British war-makers have for centuries displayed a weakness for ‘gesture strategy’ – deploying a disproportionately small force as a means of displaying interest in fulfilment of a disproportionately large objective. Mass matters, however, to the success of all military operations, and in this case it would be lacking. Though the RAF neither then nor later admitted this, its commitment to an assault on Germany’s dams was marginal, a tiny fraction of the forces that set forth upon almost nightly attempts to burn cities. To borrow a modern phrase, this would be a niche operation.
Wallis’s commitment to Upkeep, by contrast, was total, and now confronted him with a dramatic challenge. At breakneck speed he must convert his theoretical concept into a viable bomb, while work was simultaneously rushed forward on building the modified Lancasters. Avro, the plane’s manufacturers, agreed to fit the necessary electrical release gear, along with strongpoints where the bomb doors must be removed, and hydraulic power for backspin pulleys. Vickers would meanwhile make protruding retainer arms for the Upkeeps, to be attached to the strongpoints; a rotational driving mechanism; and the bombs themselves. All the latter work would be carried out at Weybridge, with Avro dispatching a team to work on the Vickers site. Wallis promised to provide working drawings of the latest version of Upkeep within ten days. Craven expressed concern about whether a revolutionary weapon of such size could be machined within the necessary time-frame.
Before the final decision, some minor obstacles had to be swept away. By coincidence Combined Operations, then headed by the frisky Lord Louis Mountbatten, was proposing an attack on the Möhne, which Mountbatten described as ‘one of the great strategic targets’. Special Operations Executive also suggested an assault by parachute saboteurs. Both bodies’ proposals were now quashed, fortunately for those who might have been charged with implementing them, in favour of what was designated Wallis’s ‘rolling bomb’. It would be the RAF which destroyed the dams of north-west Germany. Or nobody.
3
1 TARGETS
At the end of February 1943, more than six years after the RAF first discussed the feasibility of attacking Germany’s dams, and over three years since the war began, air chiefs and engineers embarked upon a ten-week dash to launch the operation that was shortly thereafter codenamed Chastise. The strategic planning – above all, about target priorities – took place within the Air Ministry. This was gall and wormwood to Sir Arthur Harris, who regarded his own headquarters staff as the only proper people to arbitrate on such matters.
Wallis, in a paper headed ‘Air Attack on Dams’ that had been circulated to a range of interested parties on the secret list back in January, identified six plausible targets – the Möhne, Eder, Sorpe, Lister, Ennepe and Henne – of which the reservoirs held a combined total of almost nine thousand million cubic feet of water, while seven other, smaller dams retained just 423 million. Breaching the Möhne alone, he promised, would cause ‘a disaster of the first magnitude’ extending to the lower reaches of the Ruhr. He appears to have intended this judgement to describe solely the industrial consequences, and to have given no consideration one way or another to the inevitable human cost among civilians caught in the path of the intended deluges, whom air-raid shelters would avail little. Thereafter, to a remarkable degree the Air Ministry made its Chastise targeting decisions on the basis of the assessment advanced by Wallis, a professional engineer but an amateur analyst of Ruhr industries.
From the Directorate of Bomber Operations, Gp. Capt. Syd Bufton* wrote to AVM Norman Bottomley, Portal’s deputy, urging the primacy of the
