IF the Germans in the autumn of 1940 had attempted to put into operation their “Sea Lion ”plan for the invasion o f England, what prospects of success would it have had ?There are, 1 think, two hypothetical situations worth consideration if we are to judge our capacity at that time to meet the threat namely, those that would have arisen :(a) had the R.A .F. tailed to win the Battle o f Britain, (b) if, having lost the Battle o f Britain, the Germans had still persisted in their plan—as for a time seems to have been their intention. Our own subsequent experience of amphibious operations, to some extent at least, enables us to judge what the chances of German success in either case would have been. We must frankly admit that our land forces were quite inadequate either to repel an assault on the beaches or to deal with the enemy successfully after he had made a landing— provided lie could have maintained his sea communications. We have since seen how even the strongest coast defences have failed to repel assault by determined troops, and how forces immensely more powerful than we then possessed proved incapable o f dealing with invading armies that had once secured a footing. \\/e now know that against the 39 well-. equipped wand ar-trained divisions the enemy intended to landon our shores we could have opposed only one fully-trained and equipped Canadian Division and another partially trained. There were, o f course, also coast defence units, the Home Guard and British troops in process o f training and re-equipment, but for lack o f transport and equipment these would have been incapable of concentrated action or large-scale man oeuvres. There was also a complete lack of armour, whereas the Germans proposed to deploy six panzer and three motorized divisions in their first assault. With such disparity o f force it is evident that no solid resistance would have been practicable once a landing had been effected. The enem y's plans for advance inland have, therefore, little interest. The utmost the defence could have hoped to achieve would have been to cause casualties, to delay the advance and possibly to deal with airborne landings but unfortunately there was no strategic reserve available with which to take advantage of time gained o r depletion o f the enem y's resources. /^UT-AND-DRIED Plans for Assault ^on Our East and South Coasts Yet the formation o f the Home Guard, and the spirit o f determination displayed, combined with an element o f bluff, had their effects. The enemy was induced to plan his invasion on a scale for which his shipping resources were inadequate, with the result that his inyasion armadas would have been cumbersome and ill-protected, offering vulnerable targets to the Navy and R.A .F. oit" whom—in the absence of adequate land (orces—the defence essentially relied. Briefly, the enemy proposed to attack in two groups on a front o f some 160 miles.“ A ”Group, composed o f his 16th and 9th Armies, was assigned the 100-mile frontage between M argate and Portsmouth. The 16th Army, starting from the ports between Ostend and Boulogne inclusive, was to land between M argate and Hastings the 9th Army starting from Dieppe. Le Havre and Caen, was to land between Brighton and “Portsmouth. B ”Group, his 6th Army, starting from C herbourg after“ A ”Group had gained a footing, was to inland Wey mouth bay. For the initial assault the two groups were to employ eleven infantry and two mountain divisions, together with a mobile force o f B y MAd.-GE N ARE L SIR CHAR LES G WYNN K .C.S .S.O.,D ."SEA -LION ”was the Nazis’ secret "code-name(* Seeloewe” in German) for their ill- starred plan for the invasion of our rhores, disclosed on September 25,1945. The map illustrates Sir Charles Gwynn’s accompanying analysis. B y courtesy of The Daily Telegraph six panzer and three motorized divisions available for rapid exploitation, and there were 17 additional divisions in reserve. On the“ A ”Group frontage airborne troops were also to be landed, and o f course it had been hoped that in the Battle o f Britain air superiority would have been gained to cover the operation. If landings had been successful, the capture of airfields would naturally have greatly increased the degree o f superiority achieved. RMANY’S Misconception of the Problems of the Great Invasion In view o f the immense disparity between the land forces available on cither side it is self-evident that the defence o f Britain depended, as indeed has always been the case, on preventing the enemy reaching our coasts in force. That is to say, he had to be attacked at his ports o f assembly, during the slow process of emerging from them, in passage and while attempting to disembark. It maybe noted that if this had successfully broken up“ A ”Group it is improbable that“ B ”Group would ever have started. Formidable as the German invading force obviously was, the whole plan for its employment was vitiated by a misconception of the nature o f the problem. The difficulties of overcoming beach defences and o f subsequent exploitation seem to have been over-estimated and the size of the force it was thought necessary to employ emphasized the difficulty o f providing shipping and craft suitable both for making the passage and effecting the landing. In addition, it clearly increased the difficulties of protecting convoys and of navigating them in an orderly manner. Comparing the successful amphibious r:----------------------------------------------- ------------—1 WHEN BRITAIN WAS HELD BY BLUFF ("~ENERAL M cNAUGHTON, who commanded the Canadian forces in Britain, threw further light, in a spccch at Detroit in October 1945, on Britain’s plight during the days of threatened invasion in 1940. "With great truth,” he said, “Britain was held largely by bluff. W e searched ancient manuscripts in the old Bodleian library at Oxford for the formula for Greek fire used in 1100 to rout the Russian Fleet at Constantinople. “Even the guns, which backdated to the era preceding the South African War, which had been placed in store by the thrifty Admiralty, were taken out and pressed into use. mounted on commcrcial vehicles of sorts, with boiler plates for armour." PAGE 420 operations o f the Allies with the abortive German plan, it is clear that material resources, especially o f shipping and suitable landing craft, were the governing factors. Although for defence the Axis powers relied landon forces, the strength o f the land force which the Allies employed for the initial landing was kept to the minimum required to again substantial footing and within the limits o f shipping available. Safety in passage, and as great an element o f surprise as could be achieved were essential to initial success, and the later development o f the strength o f the striking force depended on maintaining the safely of sea communications. ‘Failure o f the Axis defence in each case resulted not from weakness land,on but primarily, from inability to interrupt the passage o f the Allied armada on its line o f sea communications by air or naval attack. ID OYAL NAVY Could Have Played Havoc With Enemy’s Convoys In the Mediterranean, the Italian Fleet failed to intervene, and the air arm ,both there and in Norm andy, was mainly used to interfere with landing operations. Perforce in the latter operation the German naval defence was limited to the action o f U-boats and mosquito craft, but it sufficed to show the need for powerful protection o f convoys. The essential difference to be noted is that whereas the Axis relied mainly on their land forces to resist an actual landing, the British problem was to defeat the invading force in passage by sea and air action. Since the Royal Navy was never called onto intervene in the Battle o f Britain, it is impossible to say definitely how far it would have done so successfully, in spite o f the dislocation o fits dispositions caused by the loss o f French naval co-operation. The defence o f Crete does, however, provide on a small scale an analogous situation. There the Navy, although without air protection, successfully broke up all attempts at seaborne landings, compelling the Germans to depend entirely on airborne invasion. The analogy is worth examination in spite of the indifference scale :first, because the vessels the Germans employed were o f much the same order as they would have been forced to employ for an invasion o f Britain in 1940 and second, because it revealed the fact that though darkness might provide im m unity from air attack to convoys in passage it does not provide immunity from naval attack. T n view o f these considerations let us return to the chances o f German success in ths two hypothetical situations 1 suggested :*(a) Would failure o f the R.A .F. to win the Battle o f Britain have left us in a hopeless position to resist invasion? I believe it would not. We may safely presume that failure would not have entailed the complete annihilation o four air defence, but rather the withdrawal o f depleted squadrons to bases out o f orange f the enem y’s fighters and fighter-escorted bombers. From these bases they could still have attacked the enem y's shipping as it neared our coast, and during daylight have given some protection to our naval forces. Bombing of enemy embarkation ports by night could still have continued, and the Navy might have played havoc with the enem y’s convoys. (b)Once the Battle o f Britain had been won and the Navy assured o fair protection the abandonment or postponement o f the German plan was inevitable. It is, however, interesting to learn from Field-M arshal von Keitel that it was fear o f naval action that prompted the decision, presumably because all hope had been lost that the Luftwaffe would be able to prevent that most devastating form o f attack from developing.