Most Secret War

by R. V. Jones

  And as for the attack that we had thrown in for good measure along with those on the five jammers, the Despatch said:

  The success of this last attack on the Headquarters of the German Air Force Signals Intelligence must have been a major catastrophe for the enemy, and it may well be that it was an important contributory factor to the lack of enemy air reaction to the assault.

  But there was a cost. As the Official Despatch said, ‘These Radar targets were very heavily defended by flak, and low level attacks upon them demanded great skill and daring … losses among senior and more experienced pilots were heavy’. In one case, that of an attack on a ‘hoarding’ on the Hague Peninsula, I received a German eye-witness account: three of our fighters had attacked in line astern, and one was hit by flak. The pilot had dived his aircraft into the hoarding, finishing it—and himself—for ever. The German said that it was the bravest thing that he had ever seen. It was agreed on the Air Staff that if I could find who the pilot was I should write a citation for a posthumous Victoria Cross; but two of the three aircraft in the attack had crashed with their pilots lost, and we could not establish which was the aircraft which had destroyed the hoarding.

  The Official Despatch concluded: ‘These attacks saved the lives of countless soldiers, sailors and airmen on D-Day’.

  CHAPTER FORTY-FOUR

  V-1

  WHILE THE first five months of 1944 were heavily occupied with the misfortunes of Bomber Command and the coming landings in Normandy, we dared not relax our watch on the pilotless aircraft and the long range rocket. In principle, and not through pique, I could have disclaimed any further responsibility. What we had discovered by the end of 1943 had already given all the technical information necessary for countermeasures to the flying bomb: weight of warhead, size of aircraft, its speed and height, and so forth. And, indeed, now that the responsibility was firmly back with the Air Staff, which had appointed Claude Pelly as Director of Operations (Special Operations) and supported him with an inter-Service Staff, there might have seemed little more for my own Section to do. But, as I had expected, there were signs that Pelly’s staff was less able than we were to form accurate assessments of the threat. Just as I was issuing my report of 24th December 1943 on the pilotless aircraft, the Chief of Air Staff on Pelly’s advice warned that the Germans might be bombarding London with 300 tons of bombs in an eight-hour period by mid-January 1944. My own estimate was that ‘a heavy bombardment could probably not occur until March 1944, assuming that the snags shown in the present trials are overcome, and that production and training are proceeding satisfactorily’.

  In fact, production in Germany was far from proceeding satisfactorily, as we later discovered. Air attacks by Bomber Command and the Eighth Army Air Force, particularly on the Fieseler Works at Kassel, in October 1943, resulted in supplies of flying bombs to Peenemünde being halted from October 1943 to February 1944. The opening of the campaign against London had repeatedly to be postponed, and we could see from the radar plots of the Peenemünde and Zempin trials that the bomb was still not ready. Pelly had agreed that the evaluation of the radar plots should be left to me, as my Unit had developed the necessary expertise, and this work became the task of a young physicist from Ebbw Vale, David Arthen Jones, who had served as a civilian in 60 Group after graduating with First Class Honours at Bangor, and who held Welsh University ‘Blues’ for boxing, rugby, and cricket. He was in fact Glamorgan’s fast bowler and would—according to Bill Hitch, the Glamorgan coach—have been England’s fast bowler had the war not intervened, and had he decided to give up physics for full-time cricket. I had previously not believed such tales as the swinging of cricket balls by seam bowlers, particularly at Trent Bridge before lunch, until Arthen told me with modest confidence that he could do it, and I kept wicket for him while he told me what every ball would do. Watching his plots of the Baltic trials over the next few months, we could see that the reliability and accuracy of the flying bombs were rapidly improving.

  The question arose of how much damage we might expect to be inflicted on London, and we found that even the size of London was variable, according to whether one wished to minimize or maximize the expected threat. In particular, Herbert Morrison was characteristically nervous and would assume as large an area as possible, whereas others such as Lindemann would go to the other extreme. Was ‘London’ to be taken as the London postal district or the Greater London area, or what? In the end, I presented the German trials results as objectively as possible by assuming that each bomb had been aimed at Charing Cross from the south-east, and superimposing the plot of the range and bearing errors for every bomb in the Baltic trials on a map where the built-up areas of London and its suburbs were shaded in, so as to indicate the proportion of bombs which would have fallen on built-up areas.

  Fig. 27. Tracks of V-1s fired in trials at Peenemünde, May 1944, as plotted by Scientific Intelligence from the German radar plots. Comparison with Figure 22 will show the increase in accuracy since December 1943

  Figure 27 shows the plotted tracks in the Baltic trials for a few days in May 1944; comparison with Figure 22 will show how much the accuracy had improved since December 1943. Taking the end-points of all the Baltic plots for May 1944 and transferring them to a map of London on the assumption that they had been aimed instead at Charing Cross from the Abbeville area, we produced on 9th June 1944 the diagram shown in Figure 28b, which may be compared with Figure 28a which shows the actual fall of bombs in the first 24 hours of the main bombardment.

  In the meantime, the bombing campaign against the 96 ‘ski’ sites, from which the flying bombs were to be launched, was well under way, with Pelly directing the efforts of both British and American bombers. Besides the launching sites themselves, Medmenham had discovered earlier in February 1944 eight large sites that were obviously intended as supply depots, and which were heavily defended by A-A guns; these were not attacked for the time being. The effort against the ski sites was such that by the third week in April the Chiefs of Staff considered that all the ski sites would have been neutralized by the end of the month.

  By that time, however, aerial photographs showed that the Germans were building what became known as ‘modified sites’, from which the familiar skis were missing, and which could be much more rapidly erected. Even so, there were some who thought that the main danger had been averted, and Pelly himself moved from his post, in which he had never been happy, to become Chief Intelligence Officer of the Allied Expeditionary Air Force, because he thought that in this new post he would see much more action. He was succeeded in the middle of May by Air Commodore Colin Grierson who, once again, was completely new to Intelligence. On the German side, too, there had been organizational changes. The most important of these had been in December 1943 when Wachtel, instead of having an independent command in control of Flak Regiment 155W, was subordinated to a new Army Corps, the LXVth, commanded by Lieutenant General Erich Heinemann, who was to co-ordinate Wachtel’s operations with those of Major General Dornberger, who was in charge of long-range rocket development.

  Fig. 28a. Flying bombs falling on London in the first 24 hours of the main V-1 campaign

  Fig. 28b. Scatter of flying bombs on London as predicted from the Baltic trials of

  Figure 27.

  Note that both patterns tend to fall short of Central London

  About the time that Pelly left I warned that, from what I could see of notices sent to the Baltic radar plotters, ‘These announcements, coupled with the generally high rate of activity during April and early May imply either an increased degree of urgency in the trials, or that they have now reached the stage where sustained rate of fire is being tested, the missile itself having been proved satisfactory’ (13th May 1944). But Grierson’s staff as late as 11th June reported that while eight ski sites might have survived and therefore be used, the sixty-six ‘modified sites’ would not be fit for use ‘on any appreciable scale’ for the next few weeks (D. Kelly: The Defence of the United Kingd
om, p. 368). In fact, the routine watch on the launching sites had fallen into the classic error that had befallen the long watch on the battle cruisers in Brest: the watchers become so tired and jaded that they miss a vital development. On this occasion, honour was just saved because a Belgian agent reported on 10th June that a train of 33 waggons had passed through Ghent in the direction of France, with each waggon carrying three objects described as ‘rockets’. Furthermore, the bad weather that had inhibited photographic reconnaissance since 4th June cleared on 11th June, and hectic activity was visible at several of the modified sites. The Air Staff was therefore able to give a last-minute warning that the flying bomb attack was imminent.

  The first ten bombs were launched on the night of 12th/13th June. Five crashed shortly after launching, and a sixth one went missing; of the remaining four, one fell in Sussex, and the others near Gravesend, near Sevenoaks and at Bethnal Green. My first visitor the following morning was Jimmy Langley, who warmly shook my hand and congratulated me. It turned out that he had made bets regarding the day on which the first flying bomb would land in England, based on our passing prediction some months before that the day would be D+7. We had by accident hit exactly the right day, on a very general argument: assuming the Normandy landings would provoke Hitler into ordering an immediate bombardment we estimated that the reaction time of a large-ish military organization such as Wachtel’s Regiment would be about a week, and so we had therefore suggested the starting date as ‘D+7’. In fact, although Wachtel was not ready, the 65th Army Corps signalled on 6th June that he was urgently to prepare to bomb London, and the preparations took six days, enabling Jimmy Langley to win the bets which he had placed on the basis of our prediction, with a confidence that I would never have entertained myself.

  I went over to the Cabinet Office to see Cherwell, who was tending to chuckle at the insignificance of the German effort and who said, ‘The mountain hath groaned and given forth a mouse!’ I told him that the night’s effort had in my opinion been an organizational hiccup and that within a few days we should see a major bombardment. In any event, we knew that the Germans could launch twenty missiles a day at Peenemünde, so they could at least do that in France. I asked Cherwell to persuade Churchill to warn the country, but I assume that he did not do so. This was unfortunate, because I had heard Churchill say at an earlier meeting that the people of Britain would stand anything if you warned them in advance about what they were in for. And although he had in fact sounded warnings about the retaliation campaign both in 1943 and earlier in 1944, I am sure it would have helped the country, and perhaps his own position, if he had given the kind of warning on 13th June that I had suggested. As it was the Germans quickly overcame their deficiencies, and on 15th June the V-1 (as the FZG76 came to be called in Germany—‘Vergeltungs 1’—‘Retaliation 1’) campaign opened in earnest, and the people of London tended to feel that the Government had been taken unawares.

  In the 24 hours beginning at 22.30 on 15th June, Wachtel launched more than 200 flying bombs, of which 144 crossed our coasts and 73 reached Greater London. 33 bombs were brought down by the defences but eleven of these came down in the built-up area of Greater London. I was horrified to see our anti-aircraft gunners firing enthusiastically at the bombs as they crossed London, which was the worst possible thing to do. For if a bomb were hit, this made sure that it would fall on London rather than pass over and explode harmlessly beyond. Cherwell needed only the slightest persuasion to intervene, and the practice was dropped within a few days.

  The guns were at some disadvantage through a misunderstanding regarding the operational heights at which the flying bombs were operated. In December 1943 I had reported that the height band mainly used in the Peenemünde trials was six thousand to seven thousand feet, although I also mentioned that some trials were made at heights as low as fifteen hundred feet. As the trials progressed at Peenemünde in 1944, the heights were gradually brought down, and we duly mentioned the fact. What I did not know was that Air Marshal Roderick Hill, who commanded our fighters and guns, had pointed out before the campaign opened that if the bombs were to fly at heights between two and three thousand feet, our guns ‘would have a very awkward task, for between those heights the targets would be too high for the light anti-aircraft guns and too low for the mobile heavy guns which at that time could not be traversed smoothly enough to engage such speedy missiles.’ Although we reported the change in height of the Peenemünde trials as a matter of routine I would—had I known the Commander-in-Chief’s anxiety—have made the point personally to him. His views, which were presumably sent to the Air Staff, did not reach me; and our information about the reduction in height did not reach him. Once again, this was an example of the hierarchical attenuation of information, and it underlined the need for the shortest links between Operational and Intelligence Staffs—whilst preserving the independence of Intelligence.

  The fighters, on which our defences mainly depended during the first few weeks of the bombardment, quickly began to do rather well, even though they were not completely ready despite our six months’ warning regarding the performance that they would need to have. The emergency resulted in Christopher Hartley having to take his experimental squadron into action, instead of continuing to develop techniques for other squadrons to use, and so he took his squadron to Tangmere, which they shared with two squadrons from the Second Tactical Air Force. After a week or so, the Station Commander told Hartley that he had been watching all three squadrons, and that somehow Hartley got about twice as much work out of his squadron as either of the other two commanders did, and asked Hartley how he achieved it. Hartley replied that, ‘It is simple, Sir. I have the last squadron in the Air Force!’ When the Station Commander asked him what he meant, he pointed out that the Fighter Development Unit was an experimental unit, and had therefore not yet been changed over to the ‘planned servicing’ arrangements now imposed on all the regular units in the Royal Air Force.

  Since the point is of much administrative interest, it is worth further explanation. The Battle of Britain, for example, was fought on the older system of servicing in which each pilot had his own aircraft, and that aircraft was serviced by a devoted ground crew, so that they regarded themselves as part of a team with the pilot, and felt that they shared in any victories that he achieved. Obviously this could be extravagant in ground crew, and one of the early results of Operational Research was to show that substantial economies could be effected by changing over to a kind of central garage system into which aircraft were sent for servicing after each operation, and from which each pilot could draw a serviced aircraft, probably a different one from that which he last flew, for each new operation.

  The scheme succeeded in Coastal Command, where the main criterion was the number of flying hours achieved per aircraft and per unit of ground crew, so well that it was extended to the other Commands as well. But it achieved flying hours at the expense of the espirit de corps that formerly existed between air crew and ground crew; and, moreover, as one pilot pointed out to me, if you were flying with one aircraft continuously and knew its various faults, you knew those which you could, literally, live with and could therefore afford to take out even if it were not in perfect condition, whereas with one that you were drawing from a central pool you had to make sure that it was fault-free before you could risk flying it.

  The main point, though, was the esprit de corps, and this was what Hartley had meant with his ‘last squadron in the Air Force’. The enthusiasm engendered by the direct interest of the ground crew in any particular aircraft and pilot somehow drew substantially more work out of them when an emergency arose. Since this is rarely quantifiable, it is not usually taken into account by any plan to improve administrative efficiency.

  Within a few days of the opening of the V-1 bombardment a new problem arose. ‘George’, with whom I had been involved in supplying misleading information to the Germans through the agents whom they supposed to be freely operating in Britain, call
ed on me one morning and asked my advice. The dilemma facing M.I.5 was that the Germans were now telling their supposed London agents to report the times and places of flying bomb incidents in London. If, to preserve the security of possible future deceptions, we were to supply truthful information to the Germans, this would be aiding the enemy. If, on the other hand, we supplied false information, then this could be checked by German photographic reconnaissance, in which case the agents would be ‘blown’ and future deception plans ruined. What should he do?

  It immediately occurred to me that photographic reconnaissance could only reveal the points of impact, and not the times. Moreover, I knew from previous experience that while agents could usually define the place of an incident fairly well, they were likely to be wrong in other details, even the time.

  I had noticed that in the Peenemünde trials the bombs tended to fall short of the target, and now knew from the plot of bombs for the first 24 hours (which is shown on Figure 28a) that the operational bombs were also tending to fall short, the centre of gravity being in south-east London, near Dulwich. In a flash I saw that we might be able to keep the bombs falling short, which would mean fewer casualties in London as a whole, and at the same time avoid arousing any suspicions regarding the genuineness of the agents.

  We could give correct points of impact for bombs that tended to have a longer range than usual, but couple these with times of bombs which in fact had fallen short. Thus, if the Germans attempted any correlation, they might be led to think that even the bombs which they had reason to believe might have fallen short were instead tending to fall in north-west London. Therefore, if they made any correction at all, it would be to reduce the average range. This range was, incidentally, determined by an ‘air-log’ which was a small propeller which clocked up the air miles flown by the bomb, and everything depended on its having been correctly calibrated, and on due allowance for the wind. After the appropriate number of revolutions had been counted the fuel supply was cut and the missile put into a dive. It was those silent seconds between the noisy roar of the engine and the explosion on the ground that made the weapon such a nerve-racking one.