The Flying Bomb: Part Two
The V-1 Organisation
(i)ON 6TH JUNE, 1944--almost exactly four years after the British Expeditionary Force had been driven out of France--Allied forces under the supreme command of General Eisenhower landed in Normandy. The story of that exploit belongs elsewhere, and need not be recounted here. In the present context we need only note that some hours after British and American forces had set foot on the Continent, General Heinemann received instructions which led him to order Colonel Wachtel to put the V-1 into action six days later.1
By the date of the landing all four Abteilungen of Flakregiment 155 (W) had arrived in France. Some seventy to eighty 'modified' sites--apart from those constructed in the neighbourhood of Cherbourg--were virtually ready in that part of northern France which lies between the Pas-de-Calais and the Seine. The majority were aligned on London, a smaller number on Southampton. During the next six days 873 flying bombs were distributed to the sites from two underground storage depots at Nucourt and Saint-Leu-d'Esserent.* By the end of that time petrol and other fuels had also arrived in sufficient quantities to give every Abteilung a chance of firing, though not all had their full quota. Allied air attacks on railways caused considerable difficulties and led to orders that trains carrying supplies for the flying-bomb units should move only at night.
Of these events nothing was known in London before the late afternoon of 10th June. The Air Ministry then learned from a good source that a train of thirty-three wagons, each nearly sixty feet long and carrying three objects described as 'rockets', had passed through Ghent in the direction of the Franco-Belgian frontier.2
Meanwhile the Air Staff were preparing a report on the prospects of a German attack with flying bombs. On the assumption that those of the'ski sites' which had escaped destruction by Allied bombers might yet be used, they believed that an effort equivalent to that of
* See Map 29.
eight completed sites, and aimed at London, might be expected from them if in fact the enemy was ready.3 The 'modified' sites, they thought, would probably not be fit for use 'on any appreciable scale' within the next few weeks.4
Circulated on Sunday, 11th June, this document was rapidly overtaken by fresh discoveries. On the same day an improvement in the weather enabled photographic reconnaissance aircraft to visit some of the 'modified' sites for the first time since 4th June. At six of the nine sites photographed, 'much activity' was visible, and at four of them rails had been laid on the launching-ramps; at six sites a characteristic building had been completed very quickly.5 A reasonable hypothesis was that the 'rockets' mentioned in the previous day's report were flying bombs, perhaps bound ultimately for those very sites. In fact, their immediate destination was probably one or other of the storage depots.
On the morning of the 12th the Assistant Chief of the Air Staff (Intelligence) (Air Vice-Marshal F. F. Inglis) therefore warned the Chiefs of Staff and others of indications that the Germans are making energetic preparations /to bring the pilotless aircraft sites into operation at an early date'.6 The Deputy Chiefs of Staff, for their part, observing that the 'modified' sites might be capable of delivering 400 tons of high-explosive during the first ten hours of their active life, contemplated asking the Chiefs of Staff to agree on the following day to air attacks on four of the still-enigmatic'supply sites'.7 That Nucourt and Saint-Leu-d'Esserent, not the'supply sites', were now the keys to the enemy's system of supply was not yet known in London.
While the Deputy Chiefs of Staff and others in this country were considering the implications of the disclosure made by Air Vice-Marshal Inglis, on the far side of the Channel General Heinemann, Colonel Wachtel and their respective staffs were making their final preparations for an offensive due to begin that very evening--almost exactly two years after the allotment of high priority to the project by Field-Marshal Milch. On the 11th Heinemann's Chief of Staff, Colonel Eugen Walter, had discussed the outlook with Wachtel and his principal advisers, who had been summoned for the purpose to the headquarters of LXV Armee Korps near Paris. In the course of the conference Wachtel drew attention to the difficulty he had found in getting up supplies, and especially to a lack of the dummy missiles needed for testing his hastily-completed launching-sites; but, under pressure from Walter, he would seem to have assented to the order to start active operations on the 12th, though at heart he thought it a mistake. Walter claims thereupon to have placed responsibility for a good start to the offensive squarely on the regimental commander's shoulders by affirming his chief's willingness to postpone the opening
date if Wachtel was not satisfied that his troops had all they needed to ensure success. The weapon, as he claims to have pointed out, was novel, and was about to be used in conditions very different from those of the practice-ground at Zinnowitz, where technical experts were constantly at hand. But Wachtel, though he must have known that the bomb was an awkward flyer and its launching-mechanism unreliable and even dangerous, is perhaps unfairly represented as confident that his men could overcome these handicaps.
Some time after midday on the fateful 12th, Heinemann left his own headquarters for Wachtel's command post at Saleux, near Amiens, to which place the regimental staff had moved a day or two earlier from their old quarters near Beauvais. There he seems to have remained for the rest of the day and at least part of the ensuing night.
The position that evening was that 54 (or possibly 55) of the 64 launching-sites were ready, in the sense that they had been fitted with launching-mechanism; but that two-thirds of them had not yet fired a trial shot. Moreover, certain safeguards intended to precede active operations could not be taken for lack of the necessary equipment. Communication between the command post and some of the sites was made difficult by the effects of Allied bombing.
Meanwhile detailed orders for the forthcoming operation, presumably drafted by Walter, had reached Saleux. They laid down that an opening salvo, timed to reach London at twenty minutes before midnight, should be launched from all positions, and that thereafter all positions should undertake 'harassing fire' until a quarter to five on the morning of the 13th. The effort envisaged was of the order of 500 missiles. An earlier plan to co-ordinate the operation with a raid on London by aircraft of Fliegerkorps IX was cancelled in view of orders from higher authority that all available bombers must be used against the Allied bridgehead.
About a quarter of an hour before the time appointed for the opening salvo, Wachtel received the disquieting news that, in the continued absence of the safety equipment, not one of his sites was in a state to fire. In this extremity he put through--seven minutes before the salvo was due--a call to LXV Armee Korps asking permission to postpone the operation for an hour.
As Heinemann himself was still at Saleux, the request may well have struck his subordinate as odd; and it appears that not until Heinemann personally intervened in the conversation did Walter agree to the postponement.
By ten minutes to midnight, further reports from his subordinate formations had convinced the unfortunate Wachtel that even the new programme could not be kept. Making the best of a bad job, he ordered that no salvo should be attempted before 3.30 a.m. on the
13th, and that sites should undertake independent harassing fire as they became ready.
In the outcome ten bombs--and ten bombs only--were launched in the early hours of the morning. Five crashed almost immediately, and the fate of a sixth remains unknown; the other four reached Southern England. The first of them--duly heard, seen and identified by the Royal Observer Corps--crossed the North Downs 'making a noise like a Model-T Ford going up a hill' and came to earth near Gravesend at 4.18 a.m. The second fell in Sussex, the third at Bethnal Green and the fourth near Sevenoaks. The only casualties inflicted by any of the four were at Bethnal Green, where six people were killed and nine seriously injured. A little earlier the German long-range guns at Cap Gris Nez had opened fire, dropping twenty-four rounds at Folkestone and nine further inland; but there is no evidence that this contribution to the night's alarms was made at the request of Heinemann or Wachtel, or even with their knowledge.8
As soon as the extent of the fiasco became known at Heinemann's headquarters, Walter ordered on his behalf that all ramps should be camouflaged and that no more launchings should be attempted until the causes of failure had been investigated. Ultimately, after a court martial--which Wachtel afterwards declared he would have welcomed--had been threatened and dropped, the night of the 15th was chosen for a fresh attempt.
On the morning of 13th June the Chiefs of Staff considered the situation created by Wachtel's opening moved.9 Owing to the confusion of radar tracks of the missiles with those of our own aircraft and the enemy's, coupled with weather which had hampered continuous observation by Observer Posts, the number of bombs which had approached the country was not accurately known; but clearly the effort had been small. The Chiefs of Staff agreed with Air Marshal Hill that it did not justify the far-reaching deployment of guns and balloons laid down in the 'OVERLORD/DIVER' plan.10 On the other hand, attacks on the enemy's launching-sites or system of supply appeared to them a wise precaution against a resumption of the offensive. As many thousands of bomber sorties would be needed to knock out all the 'modified' sites, the Chief of the Air Staff suggested that at least part of any air effort which General Eisenhower could safely spare from 'OVERLORD' should be devoted to their four'supply sites' which seemed most worthy of attack. To deal with these about a thousand heavy bomber sorties should suffice. Lord Cherwell, who attended the discussion, deprecated a hasty acceptance of the assumption that
the'supply sites' were important; but Sir Charles Portal's view prevailed.11 Later in the day the War Cabinet agreed that the Supreme Commander should be asked to authorise heavy attacks on the'supply sites', and also attacks on all completed 'modified' sites 'in so far as this was possible without prejudicing in any way the urgent needs of the Battle in France.12 They also agreed that for the present the public need not be told that the enemy had used a new form of attack.
Meanwhile Hill had arranged that 'intruder' aircraft should visit some of the 'modified' sites; and in the outcome no other action was taken against such sites for several days. Of the four'supply sites' supposed worthy of attack, two were bombed (one of them several times) between 13th and 15th June by heavy bombers of the United States VIIIth Air Force.13 As we now know, these attacks were wasted, since the enemy was storing his supplies elsewhere.
We must now return momentarily to Wachtel and his preparations for a fresh start to the offensive. By the 15th he had so far put his house in order as to ensure that his earlier disaster would not be repeated. Well supplied with bombs and fuel, and this time better acquainted with the problems that confronted them, his troops began firing about ten o'clock that evening. The attack started with a small salvo, and 'harassing fire' continued until noon on the 16th. During that time 244 missiles aimed at London were launched from 55 'modified' sites on both sides of the Somme.14 Forty-five crashed soon after they had left the ramps. In addition about 50 bombs appear to have been aimed at Southampton and its neighbourhood.15 Up to midnight on the 16th 155 missiles were observed by the defences, 144 crossed the English coast, and 73 reached Greater London. Of those that fell outside the capital, fourteen were shot down by anti-aircraft guns and seven by fighters, while another was credited to guns and fighters jointly. In addition, guns of the Inner Artillery Zone brought down eleven bombs within London's built-up area. Many bombs miscarried, one so widely that it came to earth in Norfolk; and of those that did reach Greater London, more than two-thirds fell south of the river.
Clearly by the morning of the 16th the country was confronted with a situation very different from that of the 13th. Hill had no doubt that the time had come to give effect to the 'OVERLORD/DIVER' deployment, and at once took preliminary steps.16 At their morning meeting the Chiefs of Staff approved the execution of the plan.17 By the evening some of the artillery and balloon units concerned were on the move, and in the early hours of the 17th the first of the antiaircraft regiments to reach its destination took up its new positions.
On the morning of the 16th the Home Secretary told the House of Commons that attacks with pilotless aircraft had begun. Many
Londoners and others have since testified to the eerie impression which this news made on them; and certainly the new form of bombardment proved in some respects more trying to the nerves than the long-drawn night attacks of 1940-1941. As Hill has said in his despatch, to some at least 'an intermittent drizzle of malignant robots seemed harder to bear than the storm and thunder of the "Blitz"'.*
That afternoon the Prime Minister held a'staff conference' attended by the Secretary of State for Air (Sir Archibald Sinclair), the Chiefs of Staff or their deputies, the Deputy Supreme Commander (Air Chief Marshal Sir Arthur Tedder), Air Marshal Hill and General Pile.18 Those present agreed that Hill 'in consultation with the G.O.C.-in-C, Anti-Aircraft Command, should redistribute the gun, searchlight and balloon defences, as necessary, to counter the attacks.†19 Other decisions were that General Eisenhower should be asked to take 'all possible measures to neutralise the supply and launching sites, subject to no interference with the essential requirements of the battle in France'; that air-raid warnings should be sounded to indicate the beginning of a bout of firing, rather than the approach of individual bombs; and that for the time being antiaircraft guns both inside and outside London should continue to engage such bombs as came their way. Engagement by guns inside the London area was abandoned two days later, after experience had shown that less than half the bombs hit by anti-aircraft fire exploded in the air. Following a suggestion made at the conference, Hill decided after a few days that balloons deployed against flying bombs should be fitted with the 'double parachute link' used for normal barrages, but at first omitted from the 'DIVER' barrage because it was not designed to cope with anything moving much faster than an ordinary bomber. The device--admittedly imperfect against fast-flying missiles--provided for the severance of the middle portion of the cable, which was intended to wrap itself round the aircraft that made impact with it.
In the course of the next few days Anti-Aircraft Command and Balloon Command, led respectively by General Pile and Air Vice-Marshal W. C. C. Gell, performed great feats by completing their deployment in little more than a third of the time envisaged in the plan. By 21st June all the balloons and nearly all the guns prescribed were in position. By that date, too, eight single-engined fighter squadrons (equipped with Tempest V, Spitfire XIV, Spitfire IX and Typhoon aircraft) and four twin-engined fighter squadrons (equipped with Mosquito aircraft) were employed on flying-bomb patrols.20 On the 20th a War Cabinet 'CROSSBOW' Committee, headed by Mr.
* Supplement to London Gazette, 19th October, 1948.
† Compare p. 383.
Duncan Sandys, was set up to consider policies and plans for counter-measures.
Meanwhile about 100 bombs a day were coming within the compass of the defences. After the first day or so all were aimed at London, except a few directed at Southampton early in July by aircraft specially adapted for the purpose of air launching.* Fighters were bringing down some thirty bombs a day, guns and balloons some eight to ten. The rest flew on towards the capital, though some passed wide of it, with the result that roughly fifty bombs a day were reaching Greater London. Clearly a scale of defence designed to meet the threat from the much-bombed 'ski sites' could not match the effort of which the 'modified' sites were showing themselves capable.
Accordingly Hill and Pile agreed on a substantial reinforcement of the gun defences; and by midday on 28th June 363 heavy and 422 light guns were in position on the Downs. By the middle of July the respective figures were 376 and 392. In addition, nearly 600 light guns manned by the Royal Air Force Regiment, and some twenty to thirty of the Royal Armoured Corps, were deployed on the South Coast. Valuable contributions to Pile's abiding manpower problem were made by the Royal Navy, the Royal Marines and the Field Army.
At the same time Hill arranged to double the strength of the balloon barrage by drawing on other barrages throughout the country. Only that at Scapa Flow was left untouched. By the beginning of July a thousand balloons were in position, and were flown or grounded at the discretion of the Barrage Commander in the 'DIVER' operations room established at Biggin Hill. Within the next few days arrangements were made to add yet another 750 balloons by 8th July. By this means the barrage was extended slightly to the west, and at the same time made more dense. Elsewhere slight departures were made from the original deployment in order that bombs brought down by balloons should not fall near buildings on the southern outskirts of London and in Kent and Surrey.
Where fighters were concerned, the problem was not so much one of numbers, as of getting the best out of those which could find elbow-room. The work of the defences, said Hill, could be likened to 'a very fast game played on a very small ground'. He and his staff made strenuous efforts to step up the performance of aircrew, controllers, radar stations and Observer Posts, not only by inculcating those methods which analysis showed to be most effective, but also by improving their equipment. Hill himself made many sorties against flying bombs, and discussed his experiences with his subordinates. To raise their speed, aircraft used exclusively for 'DIVER' were deprived
* See p. 389.
of their armour and certain other fittings, and their external surfaces were stripped of paint and polished. Their engines were modified to accept more boost and special fuel.
Of the fighters used at first, the fastest were the Tempest V and the Spitfire XIV; but Hill had only a wing of each, and they could not be everywhere at once. With Leigh-Mallory's consent he therefore borrowed from Air Marshal Coningham at first a flight and later a wing of Mustang Ill's, which were designed to give their best performance at low altitudes. At night, Mosquitos were barely fast enough for the work unless their crews were exceptionally skilful; and Tempests manned by volunteers from the Mosquito squadrons proved in some respects more suitable. In any case a flying bomb could seldom be overhauled in a stern chase unless the pursuer started well above it and increased his speed by diving. Generally the most effective method was to fly on roughly the same course as an approaching bomb, allow it to catch up, and open fire as it passed. Some pilots found, however, that they could cause a bomb to crash by flying close beside it and using a wing to tip it over. Still others proved that a bomb could be similarly thrown off balance by the displaced air travelling in their wake.
Whichever procedure was adopted, the fighter had first to be brought to the right spot. Over the sea, pilots were guided either by precise instructions from controllers at radar stations on the coast, or by a running commentary on the behaviour of all bombs near them. The second method left each pilot free to choose his target, thus entailing some risk of duplicated effort. Over the land a running commentary--supplemented by various indications such as signal rockets, shell-bursts and searchlight-beams--was the only practicable system.
By the middle of July thirteen squadrons of single-engined fighters and nine Mosquito squadrons were in action against flying bombs.21 Of nearly 3,000 missiles reported by the defences up to that date--the enemy having launched about 4,000--fighters destroyed just short of a third, the majority falling in the sea or in open country or exploding in the air.* A few came down in built-up areas, despite all efforts to prevent such happenings.
If the fighters had a stiff task during the first phase of the 'battle of the bomb', that which faced the anti-aircraft gunners was in many ways more trying still. Admittedly the bomb was in some respects a perfect target. It could not dodge, and thus its course could be accurately predicted. But in other ways it was anything but a gunner's dream. It did not fly as fast as its designers planned; but, even so, moved fast enough to make an awkward mark.†22 At its normal
* For precise figures, see Appendix XLV.
† According to Dr. Gosslau, the defect responsible for the lowered speed could have been remedied without great difficulty if the German High Command had not believed that it encouraged us to divert guns and fighters from the battle in Normandy. On the other hand, there is evidence that a higher speed would have been welcomed by Heinemann and probably by others.
height of two or three thousand feet above sea-level--again a lower figure than that first contemplated--it was at once too far from the ground to suit the light guns, and too near it to suit the heavy. Heavy gun crews found that the missile crossed their field of fire too rapidly to give them all the time they needed to use their instruments and afterwards traverse the 3.7-inch mobile guns which they were manning. New devices which would ease the problem--notably the S.C.R. 584 radar set and the No. 10 Predictor--had been ordered in the United States, but had not yet reached this country in substantial numbers. The 3.7-inch static gun, which could be traversed more quickly, was on that account a better weapon, but its emplacement on concrete was too lengthy a business to meet the conditions of the battle. Brigadier J. A. E. Burls, of Headquarters, Anti-Aircraft Command, with his staff of Royal Electrical and Mechanical Engineers, went far to overcome the difficulty by devising a portable platform--popularly called the 'Pile Mattress'--which could be rapidly installed and on which the static guns could rest. Replacement of mobile by static guns was begun towards the end of June, and by the middle of the next month 32 of the static pieces had been emplaced.
At an early stage of the offensive, some changes in the disposition of both heavy and light guns were found desirable. The 'OVERLORD/ DIVER' plan provided for the siting of the heavy guns in places where their radar sets were not too much exposed to jamming, but where, in consequence, their users' task was made difficult by echoes from surrounding contours. Counter-measures taken for a wider purpose on the eve of the landing in Normandy were soon found to have made jamming so improbable that removal to higher and more favourable ground could be undertaken with negligible risk. The change--completed about the end of June--meant not only the removal of many of the guns themselves, but also the re-laying of their communications. General Pile decided, too, that he could improve the chances of the light guns by concentrating them in front of the heavy guns. In their new positions they could derive no help from the searchlight radar sets which would otherwise have been at their disposal; but Pile found that he could use them to even better purpose against 'unseen' targets by linking each troop of four guns with a heavy-gun predictor and the corresponding G.L. set.
Despite these reforms, the performance of the guns remained for some time disappointing. During the first five weeks of the offensive anti-aircraft gunners destroyed fewer than a tenth of the bombs observed by the defences. To the causes of this poor return for so
much thought and labour we shall return in a later section of this chapter.
Meanwhile offensive counter-measures were making progress after a poor start.
We have seen that the policy endorsed in the middle of June by both the Chiefs of Staff and the War Cabinet was to bring to bear against the enemy's arrangements for supply and launching the greatest number of bomber aircraft that General Eisenhower could spare from the more momentous task of supporting the troops newly lodged across the Channel. By virtue of an arrangement made in the previous winter, when attacks on'ski sites' were in question, its execution was the task of the Allied Air Commander.
The striking forces immediately available to Leigh-Mallory for the purpose comprised the light and medium bombers and the fighter-bombers of the British Second Tactical Air Force and the United States IXth Air Force, insofar as they were not committed to direct support of troops. The heavy bombers of the British Bomber Command and the United States VIIIth Air Force--on which he would largely rely to carry out the policy--were not at his direct disposal, though he could ask for their assistance.
During the past six months both Air Chief Marshal Harris and Lieutenant-General Doolittle, the respective commanders of the British and American heavy bomber forces, had contributed generously to the bombing of'ski sites' and 'large sites'. We have seen, too, that immediately after Colonel Wachtel's first bout of firing, General Doolittle met the wishes of the British Chiefs of Staff by making several attacks on two'supply sites'.
On 16th June Leigh-Mallory, having learnt from the Air Ministry that the targets whose destruction was thought most likely to hamper Wachtel were still the four'supply sites' chosen earlier, followed by eleven'ski sites' and after that by twelve 'modified' sites which showed signs of having fired, arranged with Air Chief Marshal Harris that the four'supply sites' should all be attacked by Bomber Command as soon as possible.23 Accordingly, Harris sent substantial forces to bomb them on that night and the next.
The position on the morning of the 18th was, then, that all four of the'supply sites' supposed worthy of attention had been heavily assailed during the past five days, two of them by day as well as at night. Otherwise there had been no bombing of any class of site since flying-bombs began to reach this country. Leigh-Mallory had the right to ask for further heavy-bomber attacks if he were so minded,
but not the power to insist on them. Harris and Doolittle, for their part, were not only preoccupied with their immediate task of assisting Allied troops in France by attacking the enemy's communications, but had also in mind the'strategic' offensive against German industry which they believed to be the most effective long-term contribution they could make to victory. There was thus little likelihood that they would welcome further 'CROSSBOW' operations--as attacks on objectives associated with flying bombs or rockets were called--unless persuaded that the targets suggested to them justified the diversion of their forces from objectives nearer to their hearts.
In this respect the picture presented to them during the second half of June was not encouraging. Soon after the middle of the month there was good reason to believe that installations at Nucourt, Saint-Leu-d'Esserent and Rilly-la-Montagne (the last near Rheims) were of some importance to the enemy, and more than guesswork to suggest that they might be equated with three depots which were thought to figure prominently in the German'secret weapon' programme.24 Admittedly the cardinal role in Wachtel's system which the first two were already playing had not yet been established; but the status of the'supply sites' was at least as doubtful. Yet the Air Ministry's current list of 'CROSSBOW' targets gave first place to the 'large sites', which had no known connection with the flying-bomb offensive and were included chiefly because they were suspected of being rocket-sites; second place to the 'supply sites'; and third place to launching-sites.25 By 18th June 44 'modified' sites had been identified north of the Somme, besides three in Calvados and about a score near Cherbourg.26 The fact that none had yet been found between the Somme and the Seine gave rise to the otherwise groundless assumption that 'ski sites' in that neighbourhood were being used, and to their consequent inclusion in the target-list as late as 27th June.27
To the two commanders much of this might well seem unsatisfactory. On the 18th Harris intimated that, having attacked the'supply sites' on the last two nights, he was unwilling to do so again until photographic reconnaissance had established the need.28 Moreover, neither he nor his American counterpart was confident that the problem of the 'modified' sites had been properly considered.29 The sites were notoriously hard to hit, and were so numerous that only a very heavy blow seemed likely to make much impression on them. Such an operation would need better weather than had prevailed lately. As an alternative to the series of harassing attacks implied by the relatively low place of the sites in the target-list, a major effort undertaken when the time was ripe had considerable attractions.
At 11.20 a.m. on Sunday, 18th June, a flying-bomb struck the Royal Military Chapel at Wellington Barracks, midway between
Buckingham Palace and Whitehall. Fifty-eight civilians and sixty-three members of the fighting services were killed: another twenty and forty-eight respectively were seriously injured.30 This was by far the largest number of casualties yet caused by any of the missiles; and the incident would seem to have made a strong impression on ministers, officials, commanders and staff officers.*
On the same day General Eisenhower defined his attitude to the problem of the counter-offensive by ruling that, for the time being, 'CROSSBOW' targets must take precedence over 'everything except the urgent requirements of the battle.31 As his deputy explained to the air commanders, this pronouncement clearly meant that for the moment flying-bomb and rocket targets must rank higher than the German industrial towns, aircraft factories and oil installations which were the mainstay of the'strategic bombing' plan. Accordingly, he expected a big 'CROSSBOW' effort in the immediate future, while the battle on land was still going well.32 But the commanders of the heavy bomber forces were still reluctant to amend their plans in favour of attacks on some, at any rate, of the 'CROSSBOW' targets commended to their notice. Sir Charles Portal, too, remained at the height of the flying-bomb campaign of the opinion that 'CROSSBOW' should not be allowed to detract from the offensive against German oil targets.33
The question was not, however, one for the air commanders or even for Air Chief Marshal Portal to decide. The decision lay with the Supreme Commander. His views were clear, and furthermore were in accordance with those recorded by the British War Cabinet and the British Chiefs of Staff. Air Chief Marshal Tedder continued, therefore, to urge on all concerned the necessity of giving effect to them. On 23rd June he ruled that even fleeting opportunities of attacking 'CROSSBOW' targets must be seized.34 He suggested that a part of the United States VIIIth Air Force should be held ready for the purpose. General Doolittle agreed to set aside two hundred aircraft.
Meanwhile 'large sites','supply sites' and other installations whose relevance to the flying-bomb campaign was doubtful continued to figure in the target-list. The problem of how and where to hit the enemy was, however, eased by the addition to it, during the last ten days of June, of Nucourt and Saint-Leu-d'Esserent, whose importance was now established beyond question. These were targets eminently suitable for heavy bombers. Attacks on both by the United States VIIIth Air Force during the last week of the month, followed by very heavy bombing of the second by the British Bomber Command on the nights of 4th and 7th July, caused a sharp though temporary decline in Wachtel's effort against London. Further
* The only other occasions when a single flying bomb killed or seriously injured more than 100 people in the United Kingdom were in the Strand on 30th June (198); at Turks Row, Chelsea, on 3rd July (124); and at East Barnet on 23rd August (211).
attacks on Nucourt were made on three occasions before the middle of July.
The bombing of 'modified' sites was less effective. By the middle of July sixty-eight of the eighty-eight 'modified' sites hitherto identified between the Seine and the Pas-de-Calais had received attention, but the number intact remained sufficient at jail times to handle all the bombs delivered to the launching-units.35 Attacks by the United States VIIIth Air Force on the flying-bomb assembly factory at Fallersleben on 20th and 29th June were the first of a series which contributed to the ultimate removal of the work to safer quarters adjacent to the A-4 rocket assembly plant at Niedersachswerfen. Even so, during the first five weeks of the flying-bomb campaign the Allied heavy bomber forces devoted as much of their effort to their general offensive against German industry as to 'CROSSBOW.36
Dissatisfaction with the Air Ministry's choice of 'CROSSBOW' targets came to a head about the end of the first week in July. Until that time the choice was made at the Air Ministry by the Director of Operations (Special Operations). One of his functions was to marshal, in the light of operational requirements, the evidence tendered by Air Intelligence. Without more help from outside his own directorate he was not, his critics thought, in a good position to understand the problems of all the operational commands concerned; and it was alleged that the best use was not always made of the intelligence that reached him.37 Whether those criticisms were justified or not, certainly the system was not working well; and on 8th July a spokesman of General Doolittle's superior formation suggested that it should be overhauled.
During the next few days Air Chief Marshal Tedder negotiated a new arrangement with the Air Staff and with Lieutenant-General Carl Spaatz, commanding the United States Strategic Air Forces in Europe. Henceforth the handling within the Air Ministry of intelligence bearing on 'CROSSBOW' would be solely the responsibility of Air Intelligence. An officer selected by Air Vice-Marshal Inglis would collate the material, and would then pass it to a committee of officers representing both the intelligence and the operations staffs of the Air Ministry and the United States Strategic Air Forces in Europe. The Joint 'CROSSBOW' Target Priorities Committee, as it was called, would study the collated evidence and decide what targets were most worth attacking. Before discussing the sequel, we must return to the 'DIVER' defences and their problems.
By the middle of July the defences contemplated in the 'OVERLORD/ DIVER' plan were working at full stretch and in a much-expanded form. We have seen that by that date between two and three times as many light and heavy guns as were specified in the plan were in position on the North Downs, besides roughly another 600 light guns sited further forward. The number of balloons deployed for the defence of London had risen by successive stages to twice, and then to between three and four times that first envisaged.
Despite great efforts by all concerned, the results were disappointing, largely because the expanded system did not provide the 'freedom from mutual interference' which Hill had postulated. Partly because not all the guns were in the gun-belt, but also because the weather was always a factor to be reckoned with, the ideal of separate spheres of action for the different arms of the defence was not attained. Such problems were a commonplace of air defence, and seldom permitted solutions equally acceptable to all concerned; but they were aggravated in the present case by the cramped area in which flying-bombs approaching London could be tackled. The solution adopted during the first five weeks of the campaign rested on the assumption that in perfect weather fighters had the best chance of success: accordingly in such conditions gunfire was prohibited and fighters had freedom of action from the English Channel to the forward edge of the balloon barrage. Conversely, in weather unsuitable for fighters, the gunners were free to fire as they liked. In middling weather--and middling weather is the usual lot of the United Kingdom--gunners in the gun-belt were allowed to fire up to a height of 8,000 feet, and fighters were denied entry unless in pursuit of a visible flying bomb; outside the belt the preference went to fighters, and gunners were permitted to open fire only on'seen' targets, in daylight and when no fighters were about. At best these rules imposed restrictions on the gunners which, however necessary, could not fail to be irksome; and in practice their observance in doubtful weather proved so difficult that many awkward incidents occurred. Both flying bombs and fighters moved so fast that infractions by gunners and fighters alike could scarcely be avoided. The obligations placed on gunners in the belt to cease fire if a fighter legitimately entered their sphere of action, and on those further forward to withhold it unless they were sure no fighter was approaching, were particularly onerous.
During the period of reduced activity which followed the bombing of Nucourt and Saint-Leu-d'Esserent the defences did especially well. Between 6th and 13th July they brought down 57 per cent, of the
bombs observed, as compared with 41 per cent, in the preceding week. The proportion which reached Greater London declined from 48 to 34 per cent.; but even so some twenty-five bombs a day were falling on the capital. Observing that friction between guns and fighters was probably the factor which would henceforth limit progress, Hill reluctantly concluded that further improvement was unlikely under the existing system. Indeed, progressive deterioration was not improbable if misunderstandings were allowed to multiply. As early as 10th July he decided, therefore, that the concession which permitted fighters to enter the gun-belt in certain circumstances must be withdrawn soon after the middle of the month.
At a conference held to discuss the change, General Pile pointed out that an obvious corollary was the removal to the belt of the guns which had hitherto remained outside it. Irrespective of the weather, guns and fighters would then have separate spheres of action, defined by no more complex regulation than a line drawn on the map. Moreover, once within the belt, all anti-aircraft artillery units not in action would be free to train without fear of infringing rules or of harming fighter-pilots henceforth excluded from their territory. In view of these arguments, Hill agreed to examine detailed proposals for removal to the gun-belt of all guns except a few which would stay on the coast to fire marker-bursts for the benefit of fighters. Among those strongly in favour of a new deal for the guns was Mr. Sandys in his capacity as Chairman of the War Cabinet 'CROSSBOW' Committee.
For the fighter squadrons, the arrangement proposed by General Pile would have the disadvantage of slightly cutting down their sphere of action. On the other hand, the risk of destruction at the hands of their own side would be lessened. In order that the reasons for the change should be clear to all concerned, Hill instructed his Deputy Senior Air Staff Officer, Air Commodore G. H. Ambler, to draw up an explanation for the benefit of his subordinate formations.
Air Commodore Ambler was not sure that the move proposed went far enough to solve the problem. He agreed that fighters should be banished from the gun-belt; he agreed, too, that the arguments for placing all the guns within the belt appeared well founded. But whether the belt was in the right place was another matter. Months before, deployment on the North Downs had been agreed upon largely because the folds and hollows there reduced the risk of jamming; but in recent weeks that risk had shrunk to negligible proportions. Thus one of the main arguments for the existing location of the guns had disappeared; and it might be that a better place could be found for them.
To clarify the issue, the Air Commodore decided to draw up a formal appreciation'strictly in accordance with the recommended method contained in the War Manual.38 As a result, he became
convinced that the right course was to move the gun-belt forward to the coast. In that position it would bisect the sphere of action of the fighters; but as interception over the sea and interception over the land were, to a great extent, already separate problems, Ambler felt sure that this handicap would be much outweighed by the advantages of an uninterrupted field of fire for the guns.
Ambler finished his appreciation during the night of 12th July. On the morning of the 13th he made ready to lay his conclusions before Air Marshal Hill. As it happened, Sir Robert Watson-Watt--whose work as a pioneer of radar has been mentioned in another chapter--called that morning at Hill's headquarters. Sir Robert had made an independent study of the problem. A brief discussion revealed that he had arrived at substantially the same conclusions as the Air Commodore. The two men immediately put their case before Hill and his Senior Air Staff Officer, Air Vice-Marshal W. B. Callaway.
Ambler's arguments convinced Hill that 'unless discounted by some faulty technical assumption, the tactical theory behind the case for moving all the guns to the coast was sound'. Watson-Watt confirmed that removal to the coast would much improve the performance of the radar sets on which the guns relied so largely; and his support had great weight with the Air Marshal. At the same time, the decision that Hill was asked to make was clearly a momentous one. Fighters had destroyed 883 of the 1,192 flying-bombs hitherto brought down, and no move that threatened to reduce their effectiveness could be undertaken lightly. Hill decided to give himself the better part of the day to think the matter over, and to discuss it at a conference in the late afternoon. In the meantime he asked Sir Robert--who was on his way to visit General Pile--to acquaint the General with the proposal, so that he should not come to the conference unprepared.
General Pile, with three of his staff officers, conferred with Hill at half-past five that afternoon. At the Air Marshal's request, Sir Robert Watson-Watt also attended, as did Air Vice-Marshal Saunders, of No. 11 Group, and a representative of the Allied Air Commander. Both Hill and Saunders were accompanied by members of their staffs.
The General has since told us that a plan similar to that proposed by Ambler had already been discussed at his headquarters, but was thought unlikely to secure Hill's approval. In any case the advantages of Ambler's plan from the gunners' point of view were so obvious that, when asked whether the proposed move to the coast was agreeable to him, Pile at once assented. Air Vice-Marshal Saunders, who might have been expected to demur at the bisection of the area allotted to his fighters, saw the merits of the plan and welcomed it as 'the most satisfactory that had yet been produced'.
In view of the authority which had been given to him to 'redistribute the gun, searchlight and balloon defences, as necessary, to counter the attacks',* Hill decided not to court the delay which he believed a reference to higher authority would bring, but to act at once on his own responsibility. Before the conference broke up he therefore ordered that the necessary arrangements should be set in train. A few hours later advanced parties were on their way to the coast.
After the conference the Air Marshal informed the Allied Air Commander personally of the decision he had reached. Leigh-Mallory asked whether a trial deployment on a short stretch of coast would not have been better. Hill replied that such half-measures would be worse than useless: the change, if made at all, must be made at once, before the process of emplacing the static guns on the Downs had gone too far.
During the next few days all the mobile guns in the existing belt, with their equipment, were moved to the coast and deployed from St. Margaret's Bay to Cuckmere Haven. The work of replacing heavy mobile by static guns then went on in the new positions. Almost simultaneously a demand arose for a separate deployment round the Thames Estuary, from the Blackwater to Whitstable, to protect London against flying bombs launched by aircraft from aerodromes in Holland. The moves involved 23,000 men and women--for a number of Mixed Batteries were used--and some 60,000 tons of stores and ammunition. Communications between battery and battery alone entailed the laying of 3,000 miles of cable. By dawn on 17th July all the heavy guns moved from the Downs to the South Coast were ready for action; within the next two days they were joined by the light guns, which had stayed longer in their old positions to cover the change. On the morning of 19th July the weapons ready for action on the South Coast comprised 412 heavy and 572 light guns belonging to Royal Artillery and United States Army Anti-Aircraft Artillery formations--the latter providing sixteen 90-millimetre heavy guns--besides 584 light guns manned by the Royal Air Force Regiment and twenty-eight contributed by the Royal Armoured Corps. Some 200 rocket-barrels were also in position. A month later the weapons deployed against flying bombs--including 208 heavy and 578 light guns round the Thames Estuary--totalled no less than 800 heavy guns (of which the United States Army provided eighty), more than 1,800 light guns and more than 700 rocket-barrels. An additional contribution to the eastward defence of London was made by the 'Maunsell Forts' described in Chapter XXI.
The period immediately following the move from the Downs to
* See p. 372.
the South Coast was an anxious time for Hill. Mistakenly supposing that undue sensitiveness to the difficulties of the gunners had led him to take less than a just view of the problem as a whole, the Air Staff disapproved his action.39 In their view he ought to have consulted them before ordering the change, or at least to have given them an opportunity of sending a representative to his all-important conference. He was not asked to undo what he had done, but was left in no doubt that his professional reputation would stand or fall by the result.
Fortunately for Hill and for the country, the Air Staff's fear that the better chances given to the guns would not counterbalance an inevitable decline in the achievement of the fighters was not realised. During the first week of the new deployment, the defences as a whole destroyed half the flying bombs observed, as compared with slightly less than 43 per cent, during the previous five weeks. Thereafter the figure rose steadily to 74 per cent, during the third week in August, declined next week to 62 per cent, and rose again to 83 per cent, during the last few days of Wachtel's campaign from northern France. On 28th August guns, fighters and balloons destroyed respectively 65, 23 and 2 flying bombs out of 97 which approached the country; and on that day only four reached London. By that date neither Hill nor the Germans could doubt that a substantial victory over Wachtel's weapon had been won.
To that victory the new deployment made the largest single contribution. Other important factors were the introduction, in growing numbers, of the new radar sets and predictors made in the United States, and the increasing skill and confidence of those who used them. The S.C.R. 584 radar set had been eagerly expected since February, and proved, on its arrival at the end of June, ideally suited for the work; but hitherto the need to train men in its use had prevented its employment in large quantities. Above all, the move to the coast gave the gunners an easier and more rewarding task by permitting the use of shells so fused that they burst automatically when they came within a suitable distance of the target. Thanks to American manufacturing facilities and resourcefulness, the 'proximity fuze' which conferred this benefit was now available in substantial quantities; but doubts about the effectiveness of the self-destroying device designed to prevent shells so fuzed from becoming dangerous to civilian life and property if they missed their mark would almost certainly have hampered its employment if the guns had stayed in their old positions. The value of the 'Pile mattress'--which alone made possible the rapid emplacement of static guns--we have already noted; and with the move to the coast this device also came into its own. By the middle of August 379 3.7-inch static guns were in position. As was foreseen--and as the appended table
Plate 27. German Flying Bomb about to descend near Drury Lane in London.
Plate 28. German Flying Bomb engaged and brought down at Night by Anti-Aircraft Fire.
Plate 29. German Flying Bomb Storage Depot at Saint-Leu-d'Esserent.
shows--the change entailed a set-off to the vastly increased success of the guns, in the shape of a decline in the achievement of the fighters; but constant study of their problems, coupled with the introduction of the jet-propelled Meteor fighter, enabled the latter nevertheless to destroy some 23 per cent, of the bombs observed between 17th July and 5th September, as compared with roughly 32 per cent, during the previous five weeks.* Altogether, from the beginning of the campaign in the early hours of 13th June until the descent of the last flying-bomb launched by an aircraft from a Dutch aerodrome on 5th September, the defences destroyed 3,463 of the missiles out of 6,725 observed and about 9,000 launched.
The lull that followed did not mark the end of the flying-bomb offensive; but our account of the work of the defences may be conveniently interrupted at this point.
The Joint 'CROSSBOW' Target Priorities Committee met for the first time on 21st July.40 Among its leading members were Air Commodore C. M. Grierson, Director of Operations (Special Operations), who took the chair, and Colonel R. D. Hughes of the United States Strategic Air Forces in Europe. In the light of the latest intelligence and of the carefully-considered views of Colonel Hughes, the committee had no great difficulty in deciding that storage depots and 'industrial and production centres' were much better targets than 'large sites','supply sites', or such debatable objectives as electrical power stations and buildings used by the Germans as headquarters. As Nucourt was believed to have been severely damaged recently, first place went to Rilly-la-Montagne, Saint-Leu-d'Esserent, and an additional depot (in fact intended for rockets) in the valley of the Oise. With them ranked seven 'industrial and production centres', including Peenemünde and Fallersleben. Fifty-seven 'modified' sites were recommended for harassing attacks on a lower order of priority. 'Large sites', the committee thought, should be reserved for certain experimental attacks which the United States VIIIth Air Force wished to make.
On the following day Leigh-Mallory willingly relinquished his formal responsibility for 'CROSSBOW'. His preoccupation with the battle in France left him little time for other tasks; and in practice his task of co-ordination had already devolved on Tedder. Detailed planning of operations involving more than one command would henceforth be done by the Combined Operational Planning
* See Appendix XLV.
Committee, an Anglo-American body set up some time earlier to plan'strategic' bombing missions and operations in support of them.
The revised target-list had at least the advantage of giving air commanders a clear and simple brief. At the outset the new arrangements proved, however, no more successful than the old in inducing them to assign to 'CROSSBOW' the stipulated preference over'strategic' targets, the latter drawing about four times the tonnage allotted to the former during the next fortnight.41 Moreover, perhaps inevitably, some days elapsed before the recommendations of the policy committee were reflected in the commanders' choice of targets. Between 16th and 18th July Nucourt, Rilly-la-Montagne, and Peenemünde with the adjoining Zinnowitz, were all attacked by heavy bombers. All except the first--omitted only because by the 21st it was deemed to have had enough attention--were objectives subsequently approved by the committee. But of the 4,185 tons of bombs devoted to 'CROSSBOW' during the next week, 2,723 were aimed at launching-sites, which were merely secondary targets, and less than 800 at storage depots and industrial and production centres, while 'large sites' drew nearly 700.42 The following week, however, saw a great improvement, with 2,019 out of 2,798 tons aimed at suspected storage depots and the balance at launching-sites.
On 29th July the policy committee added two more suspected storage depots and two suspected fuel dumps to its list and removed two industrial and production centres.43 The number of launching-sites recommended for harassing attack was increased to 58. Meanwhile the weight of bombs directed at 'CROSSBOW' targets of one sort or another since the start of the flying-bomb offensive in mid-June had risen to nearly 50,000 tons.
A few days later the Combined Operational Planning Committee presented a plan for a general offensive against 'CROSSBOW' targets on lines suggested by Air Chief Marshal Tedder. The United States VIIIth Air Force, contributing 1,500 sorties, were to attack Peenemünde, Fallersleben, hydrogen-peroxide plants at Ober Raderach and Düsseldorf, two suspected storage depots and twenty launching-sites. The British Bomber Command would devote 1,000 sorties to twenty-two launching-sites and three suspected storage depots. Finally the United States IXth Air Force and the British Second Tactical Air Force would together expend 400 sorties on 40 launching-sites. In this way nearly every major 'CROSSBOW' target, besides every launching-site known or suspected to have fired recently, would be assailed at one blow.
Cloudy weather, coupled with the demands made by the battle in France on the Tactical Air Forces, prevented the execution of the whole plan within twenty-four hours, as had been intended. After an unsatisfactory start the heavy bomber forces did, however,
manage to carry out the greater part of their share within a week. Between 2nd and 9th August nearly 15,000 tons of bombs were aimed at 'CROSSBOW' targets of several kinds; and further efforts during the next week brought the load expended on 'CROSSBOW' since mid-June to more than 73,000 tons. During those nine weeks more than 26,000 tons had been aimed at launching-sites alone--unfortunately, as many suspected at the time and as we now know, with little effect on Wachtel's ability to launch the bombs that reached him.
In the second half of August the problem was complicated by two new factors. One was a revival of the fear that attacks on the United Kingdom with long-range rockets might be imminent. Already, at their third meeting on 5th August, the policy committee had agreed to recommend the bombing of liquid-oxygen plants whose output might go into rockets, and of radio-beam stations whose destruction was expected to ease the work of intercepting transmissions which might be associated with the missile; later, rocket-targets bulked still larger. The other new factor was perhaps an outcome of the familiar process by which a committee originally composed of experts tends to grow into an assembly of representatives more attuned to broader issues, but less intimately acquainted with subject-matter so abstruse that its elucidation devolves increasingly on a sub-committee working in the background. Within a week of its creation the policy committee had found it expedient to delegate a great part of its labours to such a sub-committee; and in August the process went much further. At the fourth meeting of the main committee on 12th August the chair was taken by Air Commodore C. B. R. Pelly, who had succeeded Air Commodore Grierson as Director of Operations (Special Operations).44 From that date the conclusions of the working committee were no longer circulated to air commanders; instead, the commanders were given the gist of them in a summary approved by the main committee. At the same time the target-lists began to be cast in a new and much more complex form. That issued on 13th August recommended no less than 122 targets, belonging to fourteen separate classes and arranged in seven 'priorities' and ten subcategories. Its successor raised the number of recommended targets to more than 130, and the respective numbers of 'priorities' and subcategories to eight and fourteen. If they gained in comprehensiveness, the lists thus lost the simplicity of their earlier counterparts, which had confined themselves to two or three priorities, and to a relatively brief array of targets whose supposed role in the German system was not difficult to grasp.
But if the arrangement of the later lists was complex, their burden was plain. It was that rocket-targets were now quite as important as those associated with the flying bomb. In the third week of August the air commanders nevertheless preferred the latter, aiming about
1,200 tons of bombs at storage depots and fuel dumps, a hydrogen-peroxide plant, 'modified' sites, and aerodromes used or likely to be used by aircraft playing the part of mobile ramps. But the next week brought a change. Of the 4,500 tons expended on 'CROSSBOW', about 2,000 were aimed at industrial and production centres, and notably at a factory suspected of making parts for flying bombs; but rocket-targets, including 'large sites', drew the greater part of the remainder.* Finally, on 31st August and 1st September the British Bomber Command aimed nearly 3,000 tons at suspected rocket-storage depots captured shortly afterwards by Allied troops.
These attacks brought the total weight of bombs expended on 'CROSSBOW' since mid-June to 82,348 tons.45 About 8,000 tons had been aimed at targets associated primarily with the rocket, the balance at a variety of objectives known or thought to be connected with the flying bomb. Altogether, since the first attack on Peenemünde in August, 1943, the offensive against flying-bomb and rocket objectives had meant for the Anglo-American air forces the dropping of roughly 118,000 tons of bombs and the loss of nearly 450 aircraft and about 2,900 pilots or other aircrew. The share of this huge load directed at targets associated mainly with the flying bomb was nearly 98,000 tons, or rather more than forty times the weight of high-explosive which had hitherto reached London as the result of Wachtel's efforts.†
On the whole, offensive counter-measures to the flying bomb brought no direct return commensurate with the great effort devoted to them. The effects of the bombing of'ski sites' between December, 1943, and 12th June, 1944, we have already noted.‡ Of attacks made between 13th June and 1st September, those on storage depots were the most successful. A bolder investment in that class of operation might have achieved much. But the Western Allies, hampered by their failure to make a clear-cut choice between the various courses of action open to them, never achieved the singleness of purpose which might have helped them to stake successfully on information
* The precise figures--the hydrogen-peroxide plant at Peenemünde being reckoned for this purpose as a flying-bomb target--were:
Industrial and production centres 1,779 266 'Large sites' 1,234 'Modified' sites 835 Liquid-oxygen plants 223 Aerodromes 150 Radio-beam stations 41 2,764 1,764
† For details, see Appendix XLVI.
‡ See Chapter XXIII.
that fell short of certainty. Their effort, like that of the Luftwaffe against our air defences in 1940, was expended on too many targets, some of them with only a remote bearing on the main issue and some with none. Notwithstanding the devoted work of countless bomber crews and ground crews, of many intelligence officers who worked almost unceasingly to discover and confound the enemy's arrangements, and of innumerable helpers who risked death or torture to keep track of what our enemies were doing, the 'battle of the bomb' was not won by offensive counter-measures, but by the defences. It is, of course, true that the defences themselves owed much to the watch kept by intelligence, which alone enabled them to shape their plans before the arrival of the first bomb on British territory. It is also true that the counter-offensive, coupled with the general Allied offensive against German industry, did something to delay the German attack. But technical difficulties would probably, in any case, have prevented Wachtel from starting active operations more than a few weeks earlier than the date in fact achieved.
The upper hand was gained, however, only when the first and most important phase of the flying-bomb campaign was within a few weeks of its close. About the middle of August Wachtel began to withdraw his left flank in face of the Anglo-American advance.46 At the same time he started to thin out the remainder of his line. Equipment which could be removed intact was sent to depots in Holland and Germany. Units which remained on his right flank continued to fire at London until the early hours of 1st September; thereafter the remainder of the regiment withdrew to a camp near Antwerp, and soon afterwards to the neighbourhood of Deventer. Meanwhile Heinemann, accompanied by most of his staff and followed by the rest, had moved to Waterloo, near Brussels, whence he, too, removed to Deventer on 4th September. Within the next few weeks the launching-troops began to take up new positions in preparation for an offensive against Continental targets.
The United Kingdom could still be reached, however, by flying bombs launched under cover of darkness from specially-adapted Heinkel 111 aircraft. Since the end of the first week in July the third Gruppe of Kampfgeschwader 3 had been so employed. Up to the end of August the unit had aimed some three hundred bombs at London, ninety at Southampton and (on the penultimate night of the month) about a score at Gloucester.47 In the early hours of 5th September--four-and-a-half days after the last missile had come from Wachtel's ramps in northern France--the air-launching unit added, as it were, a postscript to the main offensive. Between five and six o'clock that morning nine bombs were observed approaching London from the east.
The lull of eleven days that followed, coupled with the rapid
advance of the Allied armies and the hope that they might soon get a foothold across the Rhine, was responsible for some over-sanguine statements by observers in this country. On 6th September the Vice-Chiefs of Staff reported, with insufficient warrant from the facts, that all areas from which flying bombs or rockets might be aimed at London were already, or would soon be, in our hands.48 They wisely added that this did not necessarily apply to air-launched flying bombs. Published statements in the same sense by ministers about the flying-bomb campaign led some members of the public to assume not merely that the main phase of the campaign was over--as indeed it was--but also that little further danger need be feared from long-range weapons. In fact, well over two thousand flying bombs and rockets were to be aimed at the capital in the course of the next seven months.
About the end of the first week in September the third Gruppe of Kampfgeschwader 3 moved from the bases in Holland which it had hitherto occupied to a group of aerodromes in north-west Germany. In succeeding weeks its crews were joined by others drawn from moribund bomber Gruppen. Towards the end of October the unit was transformed into the first Gruppe of Kampfgeschwader 55, and by the middle of November all three Gruppen of that Geschwader were in action.49
Operations from the new area began towards dawn on 16th September. About fifteen aircraft took part, and succeeded in launching at least nine bombs. The Royal Navy destroyed two at sea, leaving seven to come within the ken of the defences. Fighters brought down one at sea and two over the land. Of the remaining four, two fell far from London, one reached Woolwich, and the other came to earth at Barking. Further launchings were made on most nights during the rest of the month and on a number of nights in October, November, December and the first half of January. Altogether 638 bombs were observed by the defences, but the number launched would seem to have been about 1,200.50
The new phase confronted Hill and Pile with some awkward problems. Interception of launching aircraft was difficult, for they flew so low that radar stations could seldom track them well at the ranges within which they ventured. Mosquito fighters were sent towards their bases whenever they were known to be in action, but had a difficult task, especially as their airborne radar did not work well in such close proximity to the surface of the sea. Modifications to the equipment of radar stations, and control of the Mosquitos from a naval frigate (H.M.S. Caicos), or alternatively from a Wellington aircraft fitted with air-to-surface-vessel radar, proved helpful only when the phase was nearly over. Even so our aircraft made a useful contribution. Between 16th September and 14th January German
casualties included forty-one launching aircraft lost on operational flights and four destroyed on the ground. In earlier operations from Dutch bases one aircraft was lost on an operational flight and one on the ground. From first to last the launching-units lost seventy-seven aircraft from all causes.51 Although many of these losses were doubtless due to accidents arising from the hazardous nature of the work, it seems fair to credit the Mosquitos with at least the sixteen victims claimed.
Interception of the bombs themselves was a familiar problem, but one whose difficulty was increased in the new phase by the fact that all activity was now at night. In darkness the tongue of flame emitted by the pulse-jet was plainly visible; but estimation of its range had always been difficult for those not specially qualified by experience or natural aptitude. A distinguished scientist, Sir Thomas Merton, devised a simple range-finder which proved valuable; but personal skill remained the most important factor. One Tempest pilot, Squadron Leader J. Berry, was outstandingly successful, claiming more than sixty bombs at night from the summer onwards. During the phase now in question Tempests, aided by a belt of searchlights stretching from Saffron Walden and Sudbury in the north to Southend and Brightlingsea in the south, destroyed some fifty bombs over the land, while Mosquitos working further forward destroyed another score or so. The Royal Navy were credited with the destruction of ten bombs and a share in the destruction of another.
By far the biggest share of success went, however, to the antiaircraft guns. To deploy them to the best advantage threatened to be no easy matter. Although in practice the enemy did little to exploit the mobility of launching-aircraft as compared with ramps, there was always the chance that he might open fire in an unexpected quarter. We have seen that during the main offensive Hill and Pile had thought it prudent to guard the eastern approaches to London against air-launched bombs by installing guns in what was called the 'Diver Box', on the shores of the Thames Estuary. After the middle of September they further extended their left flank by adding a 'Diver Strip', stretching from the northern edge of the 'Box' to Yarmouth and held mainly by units withdrawn from the original 'Diver Belt' on the South Coast. By the middle of October 1,107 heavy and light guns were deployed in the 'Box' and 'Strip', these figures including many 37-inch static guns manned by Light Anti-Aircraft units and used in an 'intermediate' role. After a time Light Anti-Aircraft gunners so employed were found to be making a smaller contribution than had been expected, and were replaced by Heavy Anti-Aircraft gunners. Guns already installed at defended ports like Harwich, Lowestoft and Yarmouth were incorporated in the 'Strip'. In case the 'Strip' should be outflanked, a plan was made
for the addition of a 'Diver Fringe' between Skegness and Whitby. Meanwhile a start had been made with the provision of winter quarters for the 'DIVER' gunners--a task described by General Pile as equivalent to the building of a town the size of Windsor, and completed in two-and-a-half months.
For several reasons, of which the most important was the proximity of large numbers of Allied bomber aerodromes, gunners in the 'Strip' could not be given the same freedom of fire as those in the 'Belt' had enjoyed during the later stages of the main offensive. They were also handicapped by the low height at which many air-launched bombs approached the coast. New equipment for controlling low-angle fire was coming into service; but as it was still scarce, Pile had to overcome the difficulty as best he could by siting his radar sets where they were least troubled by interference from natural features, but where in consequence the length of warning they could give was less than it might otherwise have been. Despite these restrictions, the guns performed extremely well, destroying well over half the bombs which approached the 'Strip' or the 'Box' between mid-September and mid-January.* Altogether only 205 bombs aimed at London eluded the defences during those four months, and out of that number only 66 reached the capital.
The fear that the 'Diver Strip' might be outflanked was realised towards dawn on 24th December, when some fifty aircraft of Kampfgeschwader 53 set out to launch flying bombs at Manchester from points off the East Coast between Skegness and Bridlington.52 Thirty bombs crossed the coast; and though seven of them passed over the defended area of the Humber and were engaged by guns there, none was destroyed by the defences. Only one reached Manchester itself, but six fell within ten miles of the centre of the city and eleven within fifteen miles. Thirty-seven people were killed and sixty-seven seriously injured.
Hitherto Hill had been reluctant to move guns to the 'Fringe' on the mere chance that bombs might approach that particular strip of coast. Within a few hours of the attack on Manchester, however, he authorised the immediate deployment of sixty heavy guns between Skegness and Filey. Two days later they were joined by four troops of light guns, and searchlights were deployed in the 'Fringe' as an aid to fighters. On 11th January the Chiefs of^Staff approved a more far-reaching scheme involving 212 heavy guns.53 In practice, gradual additions brought the number to 88 by the end of that month, and to 152 by early March. The number of light guns remained at sixteen. Schemes were drawn up, too, for the 'DIVER' defence of the
* Namely, 321 out of 576 which reached the coast without succumbing to the Royal Navy or to fighters working to seaward of the guns.
thickly-populated areas round the Tyne, Tees, Forth and Clyde, but were never carried out. In the outcome no more flying-bomb attacks were made on any northern city.
Of offensive counter-measures between September and January there is little to be said. Soon after the close of Wachtel's offensive from northern France, the Joint 'CROSSBOW' Target Priorities Committee and the Directorate of Operations (Special Operations) ceased to function, and the Supreme Commander, with his deputy, moved across the Channel. The departure of Air Chief Marshal Tedder placed a heavier responsibility for 'CROSSBOW' on the Deputy Chief of the Air Staff, though indeed the latter had been responsible throughout for representing the views of the British Air Staff, as distinct from the Anglo-American viewpoint represented by the former. On the disbandment of the Allied Expeditionary Air Force in the middle of October, Air Defence of Great Britain regained its old name and status, Hill remaining at its head and assuming the post of Air Officer Commanding-in- Chief, Fighter Command. Thereupon Hill became responsible, at least in theory, for both defensive and offensive counter-measures to flying bombs and rockets aimed, or likely to be aimed, at the United Kingdom. As he had no aircraft capable of striking effectively at air-launching bases in north-west Germany, or of bombing still more distant industrial and production centres, his control over offensive counter-measures to the flying bomb was limited in practice to the power of making representations to other commanders or to the Air Staff.
In September the most promising objectives for such counter-measures were believed to be four aerodromes at Varrelbusch, Zwischenahn, Aalhorn and Handorf-bei-Münster.54 Long-range fighters could reach them, but only bombers could severely damage them. During the lull which followed the last launchings by aircraft from Dutch bases, the Chiefs of Staff agreed that the suspension of 'CROSSBOW' measures which they then approved should not apply to air-launching bases. These would continue to be attacked as part of a general offensive against the German air force.55 Handorf was in fact bombed on several occasions between 23rd September and the end of the first week in October; but for the moment little was achieved by these attacks.56 Towards the middle of October a heavier blow at aerodromes in north-west Germany, including Varrelbusch and Zwischenahn, was nullified by bad weather.
A few days after the reshuffle which changed Air Marshal Hill's responsibilities, two of his intelligence officers visited Air Chief Marshal Harris's headquarters at High Wycombe. Staff officers there agreed that Handorf, Varrelbusch and Aalhorn were acceptable objectives, but could not promise that they would soon be tackled. Thereupon Hill wrote informally to the Deputy Chief of the
Air Staff, expressing his concern that so little was apparently being done to check the growth of the air-launching unit.57 But the relative lightness of the German effort, the success of the defences, and the many demands then being made on Allied air power, were all arguments against his case. Another was the commencement of flying-bomb and rocket attacks on Continental cities, since this seemed likely to entail yet another claim on Anglo-American air striking power.
Nevertheless launchings by Kampfgeschwader 53 dwindled in November, and towards the middle of January ceased entirely, not for lack of flying bombs or aircraft, but because the Allied air offensive, though less particularly directed at the bases of the unit than Hill wished, was in fact enough to persuade the Germans that the bases would soon become untenable.58 About the same time the S.S. General Kammler gained virtual control of both flying-bomb and rocket operations.
Between 20th and 27th November only about a score of bombs approached the country, and during the next week none at all. Thereafter an intermittent effort culminating in the attack on Manchester was followed by another week of inactivity. In the fortnight after that the defences were troubled on four nights only. The end came shortly after 2 a.m. on 14th January, when the last air-launched bomb to reach the United Kingdom fell at Hornsey.
Meanwhile a new version of the flying bomb, with the same dimensions as the original FZG. 76 but made of lighter materials and capable of flying further, was under development at Peenemünde. In February fragments of the new missile were picked up in Belgium.59 Accordingly on the 25th of that month the Air Ministry warned the Chiefs of Staff that the United Kingdom was once more within reach of ground-launched flying bombs.60 If aimed at London, they would necessarily be despatched from western Holland, since that was the only suitable territory in German hands. In fact--as we now know--the Germans had recently constructed six new ramps there, of which three were aligned on London and the rest on Antwerp.
On the following day photographic reconnaissance revealed two of the three ramps aligned on London. As they threatened to make awkward targets, and as the enemy was thought to be in no position to do much for at least some weeks, no immediate steps were taken to attack then.61 But a plan was at once made to reinforce the 'Diver Box' and the southern part of the 'Diver Strip' by twelve batteries (96 heavy guns) to be moved from the northern part of the 'Strip' and replaced in part by six Mixed Batteries hitherto in training. In practice, reinforcement ceased in early March,when about three-quarters of the plan had been put into effect.62 In addition, three Mustang squadrons and a squadron of Meteors were chosen to work
by day, and a squadron of Tempests by night, between the guns and London, and three more Mustang squadrons and two squadrons of Mosquitos to intercept by day and night respectively to seaward of the guns. A direct link was established between the headquarters of No. 11 Group at Uxbridge and radar stations which the Second Tactical Air Force had installed in Belgium to cover the Dutch coast.
The new phase began early on 3rd March and ended less than four weeks later. During that time 275 bombs were aimed at London, but only 125 of them flew far enough to be observed by the defences. The guns, surpassing all earlier achievements, destroyed no less than 86, besides one shared with the Royal Navy. So successful were they that only the Tempest squadron and one Mustang squadron, out of the ten fighter squadrons originally allotted to the work, were called upon. The four bombs brought down by these aircraft brought the total destroyed to 91, so that only 34 eluded the defences. Thirteen reached the target.
Offensive counter-measures against the two launching-sites discovered on 26th February were taken during the third and fourth weeks of March. On the 20th and again on the 23rd fighter-bombers of Fighter Command attacked one at Ypenburg, near The Hague; the other, at Vlaardingen, near Rotterdam, was attacked on the 23rd by the Second Tactical Air Force, also with fighter-bombers. Both sites were severely damaged. The third site, in the neighbourhood of Delft, was not located until it had ceased to fire.
Greater London received its last flying bombs on the morning of the 28th, when two exploded at Chislehurst and Waltham Cross. But still the bombardment was not quite over. A few minutes before nine o'clock on the following morning the last bomb to elude the defences came down at Datchworth, a village near Hatfield; and an hour later the last to succumb to anti-aircraft fire after crossing the coast descended at Iwade, near Sittingbourne in Kent. Finally, at 12.43 P-m- that day a bomb approached the coast at Orfordness, but was successfully engaged by the guns of the 'Diver Strip' and crashed into the sea.
So ended an ordeal perhaps as trying to Londoners as any they had endured throughout the war. It had lasted, with a few short breaks, for more than nine months and had cost them almost constant worry, besides much injury to life and property. Unlike an ordinary bomb, the missile made a shallow crater. Its blast effect was proportionally widespread, so that in the crowded districts south of the river, where the bombs fell thickest, many hundreds of buildings were sometimes damaged at one blow.63 In the most frequently-hit borough, Croydon, three houses out of four are said to have suffered in one way or another from the many missiles which exploded there; and
Wandsworth and Lewisham were not far behind.* It is not surprising, therefore, that in the early stages of the offensive the output of some London factories declined markedly, partly because of the hours lost by workers in taking shelter or attending to their damaged homes, and partly because efficiency was lowered by anxiety and loss of sleep.64Later the decline was checked as local warning-systems were improved, as a bigger labour-force was made available for urgent repairs and, above all, as ordinary men and women learned to greet the buzz and rattle of approaching 'doodle bugs' with something akin to resignation. Measures which helped the Civil Defences to cope with a difficult though not unforeseen task included reinforcement of the London Civil Defence Region from other parts of the country, generous support from the Home Guard and the Women's Voluntary services and, incidentally, the use of trained dogs to trace victims buried under fallen masonry.
Outside London nerves were likewise strained by the long-drawn threat from bombs which might, and often did, fall short of the capital or pass wide of it or beyond it. The biggest sufferers were not the inhabitants of towns which happened to be secondary targets--for Portsmouth and Southampton received perhaps a sixth of the bombs intended for them, Manchester about a fiftieth and Gloucester none--but those who lived or worked where intercepted or defective bombs fell thickest. Between them those parts of Kent, Sussex and Essex which lay outside the London Civil Defence Region received more bombs than the whole of London, and the corresponding part of Surrey more than any London borough.† Many dwellers in rural districts, far from any military objectives, endured the transformation of their fields and gardens into 'graveyards for buzz-bombs stricken by the way'. But though their ordeal was severe, and though the lives of some were taken, and the homes of many more destroyed, with the result that the capital was spared some part of its agony, the fact remains that on a broad view damage was relatively light in country districts, and that about nine-tenths of the six thousand people killed and eighteen thousand seriously injured by flying bombs were dwellers or workers in London or its outskirts.65
To assess the effectiveness of the flying-bomb campaign from the standpoint of those who launched it is nevertheless no easy matter. In a sense their objects were defeated by the inaccuracy of the weapon and the success of the defences. Of roughly 10,000 missiles aimed at Central London, less than a quarter descended within the much wider boundaries of the London Civil Defence Region, an area stretching as far afield as Staines and Sunbury, Uxbridge, Elstree, Chigwell, Orpington and Esher. Of the remainder, many succumbed
* See Appendix XLVII.
† See Appendix XLVIII.
to mechanical faults, or were shot down, before they reached the coast; but roughly half flew far enough to descend on British soil when the defences, or their own mechanism, terminated their career. And though the casualties they caused were relatively light, the enemy was not far wrong if he reflected that every missile reaching the United Kingdom might do some harm, were it only to disrupt the routine of workshop or farm for half an hour. It does not derogate from the achievement of the defences to recognise these facts, or to acknowledge that the flying-bomb offensive was not altogether unavailing as a relatively cheap reply to Allied bombing.
The further hope that the campaign might check the Allied advance in Normandy by diverting guns and fighters to purely defensive tasks was less well founded. At the time some Allied commanders, eager for every weapon that might help their troops to sustain the battle, may perhaps have grudged the batteries and squadrons deployed on this side of the Channel; but probably few would claim to-day that the guns and fighters used for home defence could not be spared, or that the triumphs of Generals Montgomery and Bradley were delayed because Air Marshal Hill was destroying flying-bombs in Kent and Sussex. On the other hand, the flying-bomb campaign and its preliminaries did cause a big diversion of Anglo-American air striking power from tasks whose earlier achievement, some may think, might conceivably have hastened Germany's ultimate collapse. And whether or not there was justice in the view that'strategic' bombing was the key to victory, it is doubtless true that, from the standpoint of the enemy, a notable achievement of the campaign was that it induced the Western Allies to spend, and sometimes to waste, on objectives in France a heavy weight of bombs which they would otherwise have dropped on Germany.
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