Sea-power, when properly understood, is a wonderful thing. The passage of an army across salt water in the face of superior fleets and flotillas is an almost impossible feat. Steam had added enormously to the power of the Navy to defend Great Britain. In Napoleon’s day the same wind which would carry his flat-bottomed boats across the Channel from Boulogne would drive away our blockading squadrons. But everything that had happened since then had magnified the power of the superior navy to destroy the invaders in transit. Every complication which modern apparatus had added to armies made their voyage more cumbrous and perilous, and the difficulties of their maintenance when landed probably insuperable. At that former crisis in our Island fortunes we possessed superior and, as it proved, ample sea-power. The enemy was unable to gain a major sea battle against us. He could not face our cruiser forces. In flotillas and light craft we outnumbered him tenfold. Against this must be set the incalculable chances of weather, particularly fog. But even if this were adverse and a descent were effected at one or more points the problem of maintaining a hostile line of communications and of nourishing any lodgments remained unsolved. Such was the position in the First Great War.
But now there was the air. What effect had this sovereign development produced upon the invasion problem? Evidently if the enemy could dominate the narrow seas, on both sides of the Straits of Dover, by superior air-power, the losses of our flotillas would be very heavy and might eventually be fatal. No one would wish, except on a supreme occasion, to bring heavy battleships or large cruisers into waters commanded by the German bombers. We did not in fact station any capital ships south of the Forth or east of Plymouth. But from Harwich, the Nore, Dover, Portsmouth, and Portland we maintained a tireless, vigilant patrol of light fighting vessels which steadily increased in number. By September they exceeded eight hundred, which only a hostile air-power could destroy, and then only by degrees.
But who had the power in the air? In the Battle of France we had fought the Germans against odds of two and three to one and inflicted losses in similar proportions. Over Dunkirk, where we had to maintain continuous patrol to cover the escape of the Army, we had fought at four or five to one with success and profit. Over our own waters and exposed coasts and counties Air Chief Marshal Dowding contemplated profitable fighting at seven or eight to one. The strength of the German Air Force at this time, taken as a whole, so far as we knew—and we were well informed—apart from particular concentrations, was about three to one. Although these were heavy odds at which to fight the brave and efficient German foe, I rested upon the conclusion that in our own air, over our own country and its waters, we could beat the German Air Force. And if this were true our naval power would continue to rule the seas and oceans, and would destroy all enemies who set their course towards us.
There was of course a third potential factor. Had the Germans with their renowned thoroughness and foresight secretly prepared a vast armada of special landing-craft, which needed no harbours or quays, but could land tanks, cannon, and motor vehicles anywhere on the beaches, and which thereafter could supply the landed troops? As has been shown, such ideas had risen in my mind long ago in 1917, and were now being actually developed as the result of my directions. We had however no reason to believe that anything of this kind existed in Germany, though it is always best when counting the cost not to exclude the worst. It took us four years of intense effort and experiment and immense material aid from the United States to provide such equipment on a scale equal to the Normandy landing. Much less would have sufficed the Germans at this moment. But they had only a few ferries.
Thus the invasion of England in the summer and autumn of 1940 required from Germany local naval superiority and air superiority and immense special fleets and landing-craft. But it was we who had the naval superiority; it was we who conquered the mastery in the air; and finally we believed, as we now know rightly, that they had not built or conceived any special craft. These were the foundations of my thought about invasion in 1940. In July there was growing talk and anxiety on the subject both inside the British Government and at large. In spite of ceaseless reconnaissance and all the advantages of air photography, no evidence had yet reached us of large assemblies of transport in the Baltic or in the Rhine or Scheldt harbours, and we were sure that no movement either of shipping or self-propelled barges through the Straits into the Channel had taken place. Nevertheless preparation to resist invasion was the supreme task before us all, and intense thought was devoted to it throughout our war circle and Home Command.
As will presently be described, the German plan was to invade across the Channel with medium ships (4,000 to 5,000 tons) and small craft, and we now know that they never had any hope or intention of moving an army from the Baltic and North Sea ports in large transports; still less did they make any plans for an invasion from the Biscay ports. This does not mean that in choosing the south coast as their target they were thinking rightly and we wrongly. The east coast invasion was by far the more formidable if the enemy had had the means to attempt it. There could of course be no south coast invasion unless or until the necessary shipping had passed southwards through the Straits of Dover and had been assembled in the French Channel ports. Of this, during July, there was no sign.
We had none the less to prepare against all variants, and yet at the same time avoid the dispersion of our mobile forces, and to gather reserves. This nice and difficult problem could only be solved in relation to the news and events from week to week. The British coastline, indented with innumerable inlets, is over two thousand miles in circumference, without including Ireland. The only way of defending so vast a perimeter, any part or parts of which may be simultaneously or successively attacked, is by lines of observation and resistance around the coast or frontiers with the object of delaying an enemy, and meanwhile creating the largest possible reserves of highly-trained mobile troops so disposed as to be able to reach any point assailed in the shortest time for strong counter-attack. When in the last phases of the war Hitler found himself encircled and confronted with a similar problem he made, as we shall see, the gravest possible mistakes in handling it. He had created a spider’s web of communications, but he forgot the spider. With the example of the unsound French dispositions for which such a fatal penalty had just been exacted fresh in our memories, we did not forget the “mass of manœuvre”; and I ceaselessly inculcated this policy to the utmost extent that our growing resources would allow.
My views were in general harmony with Admiralty thought, and on July 12 Admiral Pound sent me a full and careful statement which he and the Naval Staff had drawn up in pursuance of it. Naturally and properly, the dangers we had to meet were forcefully stated. But in summing up Admiral Pound said: “It appears probable that a total of some hundred thousand men might reach these shores without being intercepted by naval forces … but the maintenance of their line of supply, unless the German Air Force had overcome both our Air Force and our Navy, seems practically impossible.… If the enemy undertook this operation he would do so in the hope that he could make a quick rush on London, living on the country as he went, and force the Government to capitulate.” I was content with this estimate.
Then in August the situation began to change in a decisive manner. Our excellent Intelligence confirmed that the operation “Sea Lion” had been definitely ordered by Hitler and was in active preparation. It seemed certain that the man was going to try. Moreover, the front to be attacked was altogether different from or additional to the east coast, on which the Chiefs of Staff, the Admiralty and I, in full agreement, still laid the major emphasis. A large number of self-propelled barges and motor-boats began to pass by night through the Straits of Dover, creeping along the French coast and gradually assembling in all the French Channel ports from Calais to Brest. Our daily photographs showed this movement with precision. It had not been found possible to re-lay our minefields close to the French shore. We immediately began to attack the vessels in transit with our small craft, and Bomber
Command was concentrated upon the new set of invasion ports now opening upon us. At the same time a great deal of information came to hand about the assembly of a German Army or Armies of Invasion along this stretch of the hostile coast, of movement on the railways, and of large concentrations in the Pas de Calais and Normandy. Large numbers of powerful long-range batteries all along the French Channel coast came into existence.
In response to the new menace we began to shift our weight from one leg to the other and to improve all our facilities for moving our increasingly large mobile reserves towards the southern front. All the time our forces were increasing in numbers, efficiency, mobility, and equipment, and in the last half of September we were able to bring into action on the south coast front sixteen divisions of high quality, of which three were armoured divisions or their equivalent in brigades, all of which were additional to the local coastal defence and could come into action with great speed against any invasion landing. This provided us with a punch or series of punches which General Brooke was well poised to deliver as might be required; and no one more capable.
All this while we could not feel any assurance that the inlets and river-mouths from Calais to Terschelling and Heligoland, with all that swarm of islands off the Dutch and German coasts (the “Riddle of the Sands” of the previous war), might not conceal other large hostile forces with small or moderate-sized ships. An attack from Harwich right round to Portsmouth, Portland, or even Plymouth, centring upon the Kent promontory, seemed to impend. We had nothing but negative evidence that a third wave of invasion harmonised with the others might not be launched from the Baltic through the Skaggerak in large ships. This was indeed essential to a German success, because in no other way could heavy weapons reach the landed armies or large depots of supply be established.
We now entered upon a period of extreme tension and vigilance. We had of course all this time to maintain heavy forces north of the Wash, right up to Cromarty; and arrangements were perfected to draw from these should the assault declare itself decidedly in the south. The abundant intricate railway system of the Island and our continued mastery of our home air would have enabled us to move with certainty another four or five divisions to reinforce the southern defence if it were necessary on the fourth, fifth, and sixth days after the enemy’s full effort had been exposed.
A very careful study was made of the moon and the tides. We thought that the enemy would like to cross by night and land at dawn; and we now know the German Army Command felt like this too. They would also be glad of a half-moonlight on the way over, so as to keep their order and make their true landfall. Measuring it all with precision, the Admiralty thought the most favourable conditions for the enemy would arise between the 15th and 30th of September. Here also we now find that we were in agreement with our foes. We had little doubt of our ability to destroy anything that got ashore on the Dover promontory or on the sector of coast from Dover to Portsmouth, or even Portland. As all our thoughts at the summit moved together in harmonious and detailed agreement, one could not help liking the picture which presented itself with growing definition. Here perhaps was the chance of striking a blow at the mighty enemy which would resound throughout the world. One could not help being inwardly excited alike by the atmosphere and the evidence of Hitler’s intention which streamed in upon us. There were indeed some who on purely technical grounds, and for the sake of the effect the total defeat and destruction of his expedition would have on the general war, were quite content to see him try.
In July and August we had asserted air mastery over Great Britain, and were especially powerful and dominant over the Home Counties of the south-east. Vast intricate systems of fortifications, defended localities, anti-tank obstacles, block-houses, pill-boxes, and the like laced the whole area. The coastline bristled with defences and batteries, and at the cost of heavier losses through reduced escorts in the Atlantic, and also by new construction coming into commission, the flotillas grew substantially in numbers and quality. We had brought the battleship Revenge, and the old target-ship and dummy-battleship Centurion, and a cruiser to Plymouth. The Home Fleet was at its maximum strength and could operate without much risk to the Humber and even to the Wash. In all respects therefore we were fully prepared.
Finally, we were already not far from the equinoctial gales customary in October. Evidently September was the month for Hitler to strike if he dared, and the tides and the moon-phase were favourable in the middle of that month.
It is time to go over to the other camp and set forth the enemy’s preparations and plans as we now know them.
CHAPTER XI
OPERATION “SEA LION”
SOON after war broke out on September 3, 1939, the German Admiralty, as we have learned from their captured archives, began their Staff study of the invasion of Britain. Unlike us, they had no doubt that the only way was across the narrow waters of the English Channel. They never considered any other alternative. If we had known this it would have been an important relief. An invasion across the Channel came upon our best-defended coast, the old sea front against France, where all the ports were fortified and our main flotilla bases and in later times most of our airfields and air-control stations for the defence of London were established. There was no part of the Island where we could come into action more quickly or in such great strength with all three Services. Admiral Raeder was anxious not to be found wanting should the demand to invade Britain be made upon the German Navy. At the same time he asked for a lot of conditions. The first of these was the entire control of the French, Belgian, and Dutch coasts, harbours, and river-mouths. Therefore the project slumbered during the Twilight War.
Suddenly all these conditions were surprisingly fulfilled, and it must have been with some misgivings but also satisfaction that on the morrow of Dunkirk and the French surrender he could present himself to the Fuehrer with a plan. On May 21 and again on June 20 he spoke to Hitler on the subject, not with a view to proposing an invasion, but in order to make sure that if it were ordered the planning in detail should not be rushed. Hitler was sceptical, saying that “he fully appreciated the exceptional difficulties of such an undertaking”. He also nursed the hope that England would sue for peace. It was not until the last week in June that the Supreme Headquarters turned to this idea, nor till July 2 that the first directive was issued for planning the invasion of Britain as a possible event. “The Fuehrer has decided that under certain conditions—the most important of which is achieving air superiority—a landing in England may take place.” On July 16 Hitler issued his directive: “Since England in spite of her militarily hopeless position shows no sign of coming to terms, I have decided to prepare a landing operation against England, and if necessary to carry it out.… The preparations for the entire operation must be completed by mid-August.” Active measures in every direction were already in progress.
Sketch Map of GERMAN INVASION PLAN
The German Navy plan was essentially mechanical. Under the cover of heavy-gun batteries firing from Gris-Nez towards Dover, and a very strong artillery protection along the French coast in the Straits, they proposed to make a narrow corridor across the Channel on the shortest convenient line and to wall this in by minefields on either side, with outlying U-boat protection. Through this the Army was to be ferried over and supplied in a large number of successive waves. There the Navy stopped, and on this the German Army chiefs were left to address themselves to the problem.
Considering that we could, with our overwhelming naval superiority, tear these minefields to pieces with small craft under superior air-power and also destroy the dozen or score of U-boats concentrated to protect them, this was at the outset a bleak proposition. Nevertheless, after the fall of France anyone could see that the only hope of avoiding a long war, with all that it might entail, was to bring Britain to her knees. The German Navy itself had been, as we have recorded, knocked about in a most serious manner in the fighting off Norway; and in their crippled condition they could not offer mor
e than minor support to the Army. Still, they had their plan, and no one could say that they had been caught unawares by good fortune.
The German Army Command had from the first regarded the invasion of England with considerable qualms. They had made no plans or preparations for it; and there had been no training. As the weeks of prodigious, delirious victory succeeded one another they were emboldened. The responsibility for the safe crossing was not departmentally theirs, and, once landed in strength, they felt that the task was within their power. Indeed, already in August Admiral Raeder felt it necessary to draw their attention to the dangers of the passage, during which perhaps the whole of the Army forces employed might be lost. Once the responsibility for putting the Army across was definitely thrust upon the Navy, the German Admiralty became consistently pessimistic.
On July 21 the heads of the three Services met the Fuehrer. He informed them that the decisive stage of the war had already been reached, but that England had not yet recognised it and still hoped for a turn of fate. He spoke of the support of England by the United States and of a possible change in German political relations with Soviet Russia. The execution of “Sea Lion”, he said, must be regarded as the most effective means of bringing about a rapid conclusion of the war. After his long talks with Admiral Raeder, Hitler had begun to realise what the crossing of the Channel, with its tides and currents, and all the mysteries of the sea, involved. He described “Sea Lion” as “an exceptionally bold and daring undertaking”. “Even if the way is short, this is not just a river crossing, but the crossing of a sea which is dominated by the enemy. This is not a case of a single-crossing operation, as in Norway; operational surprise cannot be expected; a defensively-prepared and utterly determined enemy faces us and dominates the sea area which we must use. For the Army operation forty divisions will be required. The most difficult part will be the material reinforcements and stores. We cannot count on supplies of any kind being available to us in England.” The prerequisites were complete mastery of the air, the operational use of powerful artillery in the Dover straits, and protection by minefields. “The time of year,” he said, “is an important factor, since the weather in the North Sea and in the Channel during the second half of September is very bad, and the fogs begin in the middle of October. The main operation must therefore be completed by September 15, for after that date co-operation between the Luftwaffe and the heavy weapons becomes too unreliable. But as air co-operation is decisive it must be regarded as the principal factor in fixing the date.”
The Second World War Page 44
