The German air crews soon suspected that their beams were being mauled. There is a story that during these two months nobody had the courage to tell Goering that his beams were twisted or jammed. In his ignorance he pledged himself that this was impossible. Special lectures and warnings were delivered to the German Air Force, assuring them that the beam was infallible, and that anyone who cast doubt on it would be at once thrown out. We suffered, as has been described, heavily under the Blitz, and almost anyone could hit London anyhow. Of course, there would in any case have been much inaccuracy, but the whole German system of bombing was so much disturbed by our counter-measures, added to the normal percentage of error, that not more than one-fifth of their bombs fell within the target areas. We must regard this as the equivalent of a considerable victory, because even the fifth part of the German bombing, which we got, was quite enough for our comfort and occupation.
* * * * *
The Germans, after internal conflicts, at last revised their methods. It happened, fortunately for them, that one of their formations,
Kampf Gruppe
100, was using a special beam of its own. It called its equipment the “X apparatus,” a name of mystery which, when we came across it, threw up an intriguing challenge to our Intelligence. By the middle of September we had found out enough about it to design counter-measures, but this particular jamming equipment could not be produced for a further two months. In consequence
Kampf Gruppe
100 could still bomb with accuracy. The enemy hastily formed a pathfinder group from it, which they used to raise fires in the target area by incendiary bombs, and these became the guide for the rest of the de-Knickebeined Luftwaffe.
Coventry, on November 14/15, was the first target attacked by the new method. Although our new jamming had now started, a technical error prevented it from becoming effective for another few months. Even so, our knowledge of the beams was helpful. From the settings of the hostile beams and the times at which they played we could forecast the target and the time, route and height of attack. Our night-fighters had, alas! at this date neither the numbers nor the equipment to make much use of the information. It was nevertheless invaluable to our fire-fighting and other Civil Defence services. These could often be concentrated in the threatened area and special warnings given to the population before the attack started. Presently our counter-measures improved and caught up with the attack. Meanwhile decoy fires, code-named “Starfish,” on a very large scale were lighted by us with the right timing in suitable open places to lead the main attack astray, and these sometimes achieved remarkable results.
By the beginning of 1941 we had mastered the “X apparatus”; but the Germans were also thinking hard, and about this time they brought in a new aid called the “Y apparatus.” Whereas the two earlier systems had both used cross-beams over the target, the new system used only one beam, together with a special method of range-finding by radio, by which the aircraft could be told how far it was along the beam. When it reached the correct distance, it dropped its bombs. By good fortune and the genius and devotion of all concerned, we had divined the exact method of working the “Y apparatus” some months before the Germans were able to use it in operations, and by the time they were ready to make it their pathfinder, we had the power to render it useless. On the very first night when the Germans committed themselves to the “Y apparatus,” our new counter-measures came into action against them. The success of our efforts was manifest from the acrimonious remarks heard passing between the pathfinding aircraft and their controlling ground stations by our listening instruments. The faith of the enemy air crews in their new device was thus shattered at the outset, and after many failures the method was abandoned. The bombing of Dublin on the night of May 30/31, 1941, may well have been an unforeseen and unintended result of our interference with “Y.”
General Martini, the German chief in this sphere, has since the war admitted that he had not realised soon enough that the “high-frequency war” had begun, and that he underrated the British Intelligence and counter-measures organisation. Our exploitation of the strategic errors which he made in the Battle of the Beams diverted enormous numbers of bombs from our cities during a period when all other means of defence either had failed or were still in their childhood. These were, however, rapidly improving under the pressure of potentially mortal attack. Since the beginning of the war we had brought into active production a form of air-borne radar called “A.I.,” on which the Air Defence Research Committee had fruitfully laboured from 1938 onward, and with which it was hoped to detect and close on enemy bombers. This apparatus was too large and too complicated for a pilot to operate himself. It was, therefore, installed in two-seater Blenheims, and later in Beaufighters, in which the observer operated the radar, and directed his pilot until the enemy aircraft became visible and could be fired on – usually at night about a hundred yards away. I had called this device in its early days “the Smeller,” and longed for its arrival in action. This was inevitably a slow process. However, it began. A widespread method of ground-control interception grew up and came into use. The British pilots, with their terrible eight-gun batteries, in which cannon-guns were soon to play their part, began to close – no longer by chance but by system – upon the almost defenceless German bombers.
The enemy’s use of the beams now became a positive advantage to us. They gave clear warning of the time and direction of the attacks, and enabled the night-fighter squadrons in the areas affected and all their apparatus to come into action at full force and in good time, and all the anti-aircraft batteries concerned to be fully manned and directed by their own intricate science, of which more later. During March and April the steadily rising rate of loss of German bombers had become a cause of serious concern to the German war chiefs. The “erasing” of British cities had not been found so easy as Hitler had imagined. It was with relief that the German Air Force received their orders in May to break off the night attacks on Great Britain and to prepare for action in another theatre.
Thus, the three main attempts to conquer Britain after the fall of France were successively defeated or prevented. The first was the decisive defeat of the German Air Force in the Battle of Britain during July, August, and September. Instead of destroying the British Air Force and the stations and air factories on which it relied for its life and future, the enemy themselves, in spite of their preponderance in numbers, sustained losses which they could not bear. Our second victory followed from our first. The German failure to gain command of the air prevented the cross-Channel invasion. The prowess of our fighter pilots, and the excellence of the organisation which sustained them, had in fact rendered the same service – under conditions indescribably different – as Drake and his brave little ships and hardy mariners had done three hundred and fifty years before, when, after the Spanish Armada was broken and dispersed, the Duke of Parma’s powerful army waited helplessly in the Low Countries for the means of crossing the Narrow Seas.
The third ordeal was the indiscriminate night-bombing of our cities in mass attacks. This was overcome and broken by the continued devotion and skill of our fighter pilots, and by the fortitude and endurance of the mass of the people, and notably the Londoners, who, together with the civil organisations which upheld them, bore the brunt. But these noble efforts in the high air and in the flaming streets would have been in vain if British science and British brains had not played the ever-memorable and decisive part which this chapter records.
* * * * *
There is a useful German saying, “The trees do not grow up to the sky.” Nevertheless, we had every reason to expect that the air attack on Britain would continue in an indefinite crescendo. Until Hitler actually invaded Russia we had no right to suppose it would die away and stop. We therefore strove with might and main to improve the measures and devices by which we had hitherto survived and to find new ones. The highest priority was assigned to all forms of radar study and application. Scientists and technicians were engaged and organised on a very large scale. Labour and material were made available to the fullest extent. Other methods of striking down the hostile bomber were sought tirelessly, and for many months to come these efforts were spurred by repeated, costly, and bloody raids upon our ports and cities. I will mention three developments, constantly referred to in the Appendices to this Volume, in which, at Lindemann’s prompting and in the light of what we had studied together on the Air Defence Research Committee of pre-war years, I took special interest and used my authority. These were, first, the massed discharge of rockets, as a reinforcement of our anti-aircraft batteries; secondly, the laying of aerial mine curtains in the path of a raiding force by means of bombs with long wires descending by parachutes; thirdly, the search for fuzes so sensitive that they did not need to hit their target, but would be set off by merely passing near an aircraft. Of these three methods on which we toiled with large expenditure of our resources, some brief account must now be given.
None of these methods could come to fruition in 1940. At least a year stood between us and practical relief. By the time we were ready to go into action with our new apparatus and methods, the enemy attack they were designed to meet came suddenly to an end, and for nearly three years we enjoyed almost complete immunity from it. Critics have therefore been disposed to underrate the value of these efforts, which could only be proved by major trial, and in any case in no way obstructed other developments in the same sphere.
* * * * *
By itself beam-distortion was not enough. Once having hit the correct target, it was easy for the German bombers, unless they were confused by our “Starfish” decoy fires, to return again to the glow of the fires they had lit the night before. Somehow they must be clawed down. For this we developed two new devices, rockets and aerial mines. By fitting our antiaircraft batteries with radar, it was possible to predict the position of an enemy aircraft accurately enough, provided it continued to fly in a straight line at the same speed; but this is hardly what experienced pilots do. Of course they zigzagged or “weaved,” and this meant that in the twenty or thirty seconds between firing the gun and the explosion of the shell they might well be half a mile or so from the predicted point.
A wide yet intense burst of fire round the predicted point was an answer. Combinations of a hundred guns would have been excellent, if the guns could have been produced and the batteries manned and all put in the right place at the right time. This was beyond human power to achieve. But a very simple, cheap alternative was available in the rocket, or, as it had been called for secrecy, the Unrotated Projectile (U.P.). Even before the war Dr. Crow, in the days of the Air Defence Research Committee, had developed two-inch and three-inch rockets which could reach almost as high as our anti-aircraft guns. The three-inch rocket carried a much more powerful warhead than a three-inch shell. It was not so accurate. On the other hand, rocket projectors had the inestimable advantage that they could be made very quickly and easily in enormous numbers without burdening our hard-driven gun factories. Thousands of these U.P. projectors were made, and some millions of rounds of ammunition. General Sir Frederick Pile, an officer of great distinction, who was in command of our anti-aircraft ground defences throughout the war, and who was singularly free from the distaste for novel devices so often found in professional soldiers, welcomed this accession to his strength. He formed these weapons into huge batteries of ninety-six projectors each, manned largely by the Home Guard, which could produce a concentrated volume of fire far beyond the power of anti-aircraft artillery.
I worked in increasing intimacy throughout the war with General Pile, and always found him ingenious and serviceable in the highest degree. He was at his best not only in these days of expansion, when his command rose to a peak of over three hundred thousand men and women and twenty-four hundred guns, apart from the rockets, but also in the period which followed after the air attack on Britain had been beaten off. Here was a time when his task was to liberate the largest possible numbers of men from static defence by batteries, and, without diminishing the potential fire-power, to substitute the largest proportion of women and Home Guard for regulars and technicians. But this is a story which must be told in its proper place.
The task of General Pile’s command was not merely helped by the work of our scientists; as the battle developed, their aid was the foundation on which all stood. In the daylight attacks of the Battle of Britain, the guns had accounted for two hundred and ninety-six enemy aircraft, and probably destroyed or damaged seventy-four more. But the night raids gave them new problems which, with their existing equipment of only searchlights and sound locators, could not be surmounted. In four months from October 1 only about seventy aircraft were destroyed. Radar came to the rescue. The first of these sets for directing gunfire was used in October, and Mr. Bevin and I spent most of the night watching them. The searchlight beams were not fitted till December. However, much training and experience were needed in their use, and many modifications and refinements in the sets themselves were found necessary. Great efforts were made in all this wide field, and the spring of 1941 brought a full reward.
During the attacks on London in the first two weeks of May – the last of the German offensive – over seventy aircraft were destroyed, or more than the four winter months had yielded. Of course, in the meanwhile the number of guns had grown. In December there had been 1450 heavy guns and 650 light; in May there were 1687 heavy guns, 790 light, with about 40 rocket batteries.
1
But the great increase in the effectiveness of our gun defences was due in its origin to the new inventions and technical improvements which the scientists put into the soldiers’ hands, and of which the soldiers made such good use.