INVASION

England has not been invaded since A.D. 1066, when, the country having no fleet in being, William the Conqueror effected a landing and subjugated the kingdom. During the eight centuries and more that have since elapsed, every country in Europe has been invaded and its capital occupied, in many cases more than once. It is by no means for lack of attempts to invade her that England has been spared the calamity of invasion for more than eight hundred years. It is not because she has had at all times—it may indeed be doubted if she has had at any time—organized military force sufficient to repel an invader, if he could not be stopped at sea. It is because she can only be invaded across the sea, and because whenever the attempt has been made she has always had naval force sufficient to bring the enterprise to nought. It is merely a truism to say that the invasion of hostile territory across the sea is a much more difficult and hazardous enterprise than the crossing of a land frontier by organized military force. But it is no truism to say that the reason why it is so much more difficult and more hazardous is that there is no real parallel between the two cases. I assume a vigorous defensive on the part of the adversary assailed in both cases—a defensive which, though commonly so called, is really offensive in its nature. The essential difference lies in this, that two countries which are separated by the sea have no common frontier. Each has its own frontier at the limit of its territorial waters, but between these two there lies a region common to both and from which neither can be excluded except by the superior naval force of the other.

For the moment an expeditionary force emerges from its own territorial waters—which may be any distance from a few miles up to many thousands of miles from the territorial waters of the adversary to be assailed—it must be prepared to defend itself, and naval force alone can afford it an adequate measure of defence. Military forces embarked in transports are defenceless and practically unarmed. They cannot defend themselves with their own arms, nor can the transports which carry them be so armed as to afford adequate defence against the smallest warship afloat, least of all against torpedo craft. Hence, unless the sea to be traversed has been cleared of the naval forces of the enemy beforehand, the invading military force must be covered by a naval force sufficient to overcome any naval force which the enemy is able to bring against it. If the latter can bring a fleet—as he must be able to do if the invasion is to be prevented—the covering fleet must be able to beat any fleet that he can bring. That condition being satisfied, however, it is clear that the covering fleet must be terribly hampered and handicapped in the ensuing conflict by the presence of a huge and unwieldy assemblage of unarmed transports filled with disarmed men, and by the consequent necessity of defending it against the attack of those portions of the enemy's naval force to which, albeit not suitable for engaging in the principal conflict, the transports would offer an otherwise defenceless prey. Hence the escorting fleet must be stronger than its adversary in a far larger proportion than it need be if naval issues pure and simple were alone at stake—so strong indeed that, if the transports were out of the way, its victory might be taken as certain. But if that is so it is manifest that the prospects of successful invasion would be immeasurably improved by seeking to decide the naval issue first—as Tourville very properly did in the Beachy Head campaign—and keeping the transports in hand and in port until it had been decided in favour of the intending invader. This is the eternal dilemma of invasion across a sea of which the command has not previously been secured. If you are not strong enough to dispose of the enemy's naval force you are certainly not strong enough to escort an invading force—itself helpless afloat—across the sea in his teeth. If you are strong enough to do this you will certainly be wise to beat him first, because then there will be nothing left to prevent the transit of your troops. In other words, command of the sea, if not absolutely and in all cases indispensable to a successful invasion, is at any rate the only certain way of ensuring its success.

Naval history from first to last is full of illustrations of the principles here expounded. I will examine one or two of them, and I must take my illustrations mainly from the naval history of Britain, first, because Britain, being an island, is the only country in Europe which cannot be invaded except across the sea, and secondly, because Britain for that very reason has often been subjected to attempts at invasion and has always frustrated them by denying to her adversary that sufficiency of sea control which, if history is any guide, is essential to successful invasion. But first I will examine two cases which might at first sight seem to militate against the principles I have enunciated. The brilliant campaign of CÆsar which ended in the overthrow of Pompey and his cause at Pharsalus, was opened by CÆsar's desperate venture of carrying his army across the Adriatic to the coast of Epirus, although Pompey's fleet was in full command of the waters traversed. This is one of those exceptions which may be said to prove the rule. CÆsar had no alternative. Pompey was in Illyria, and if CÆsar could not overthrow Pompey on that side of the Adriatic it was certain that Pompey would overthrow CÆsar on the other side. For this reason, and perhaps for this reason alone, CÆsar was compelled to undertake a venture which he must have known to be desperate. How desperate it was is shown by the fact that, not having transports enough to carry more than half his army at once, he had to send his transports back as soon as he had landed, and they were all destroyed on their way back to Brundusium. Antony his lieutenant did, indeed, succeed after a time in getting the remainder of his army across, but not before CÆsar had been reduced to the utmost straits. The whole enterprise moreover was not, strictly speaking, an invasion of hostile territory. The inhabitants of the territory occupied by both combatants were neutral as between them, and were willing to furnish CÆsar with such scanty supplies as they had. Again, an army in those days needed no ammunition except the sword which each soldier carried on his person, and that kind of ammunition was not expended in fighting. Hence CÆsar had no occasion to concern himself with the security of his communications across the sea—a consideration which weighs with overwhelming force on the commander of a modern oversea expedition. "A modern army," as the late Lord Wolseley said, "is such a complicated organism that any interruption in the line of communications tends to break up and destroy its very life." An army marches on its belly. If it cannot be fed it cannot fight. After the Battle of Talavera Wellington was so paralysed by the failure of the Spanish authorities to supply his troops with food that he had to abandon the offensive for a time and to retreat towards his own line of communication with the sea. CÆsar on the other hand abandoned the sea, which could not feed him, and trusted to the resources of the country. The difference is vital. The one risk that CÆsar ran was the destruction of his army afloat, and that he ran not because he chose but because he must. The risk of destruction on land he was prepared to run, and this, at any rate, was, as the event proved, a case of bene ausus vana contemnere.

Again, Napoleon's descent on Egypt is another exception which proves the rule, and proves it still more conclusively. Napoleon evaded Nelson's fleet and landed his army in Egypt. The army so landed left Egypt in British transports, having laid down its arms and surrendered just before the conclusion of the Peace of Amiens; and but for the timely conclusion of that short-lived armistice, every French soldier who survived the Egyptian campaign might have seen the inside of a British prison. This was because Napoleon, who never fathomed the secrets of the sea, chose to think that to evade a hostile fleet was the same thing as to defeat it. He managed for a time to escape Nelson's attentions by the skin of his teeth, and fondly fancied that because he had done so the dominion of the East was won. He was quickly undeceived by the Battle of the Nile. That victory destroyed the fleet which had escorted his army to Egypt and thereby made it impossible for the army ever to return except by consent of the Power which he never could vanquish on the sea. The Battle of the Nile, wrote a Frenchman in Egypt, "is a calamity which leaves us here as children totally lost to the mother country. Nothing but peace can restore us to her." Nothing but the so-called Peace of Amiens did restore them. If it be argued, as it often has been, that Napoleon's successful descent on Egypt proves that military enterprises of large moment may sometimes be undertaken without first securing the command of the sea to be traversed, surely the Battle of the Nile and its sequel are a triumphant refutation of such an argument. Such enterprises are merely a roundabout way of presenting the belligerent who retains the command of the sea with as many prisoners of war as survive from the original expedition.

I need not labour the point which the unbroken testimony of history from the time of the Norman Conquest has established, that all attempts to invade England have been made in the past and must be made in the future across a sea not commanded by the intending invader. If he has secured the command of the sea beforehand, there is nothing to prevent the invasion except the consideration that he can attain his end—that is, the subjugation of the nation's will—at less cost to himself. That being premised, let us consider how the intending invader will set about his task. There are three ways, and three ways only. First, he may seek to overpower the British naval defence on the seas, that is to obtain the command of the sea. If he can do that, the whole thing is done. Or secondly, he may collect the military forces destined for the invasion in ports suitable for the purpose, and when all is ready he may cover their embarkation and transit by a naval force sufficient to overcome any naval force which this country can direct against it. I have already shown, however, that a force sufficient to do this with any certainty, or even with any reasonable prospect of success, must needs be more than sufficient to overpower the British naval defence and thereby to secure the command of the sea, if the enemy were freed from the entangling and wellnigh disabling necessity of providing for the safe conduct of an unwieldy host of otherwise defenceless transports. In other words he is putting the cart before the horse, a procedure which has never yet succeeded in getting the cart to its destination. This second alternative is then merely a clumsy and extremely inefficient way of attaining the same end as the first, and need only be mentioned in order to exclude it from further consideration.

There remains only a third alternative. This is to assemble the invading military force at suitable ports as before, and to attempt to engage the attention of the defending naval force by operations at a distance for a time sufficient to secure the unmolested transit of the military expedition. This is the method which has nearly always been employed by an enemy projecting an invasion of this country. It has never yet succeeded, because it always leads in the end to a situation which is practically indistinguishable from that involved in the second alternative, which I have already discussed and excluded. The naval and the military elements in the enterprise of invasion being now, by the hypothesis, separated in space and for that reason incapable of being very exactly combined in time, a whole series of highly indeterminate factors is thereby introduced into the problem to be solved by the invader. There are elements of naval force, to wit, all manner of small craft, which are not required for the main conflict of fleets—and it is this conflict which alone can secure the command of the sea—but which are eminently adapted for the impeachment and destruction of unarmed transports. These will be employed in the blockade of the ports in which the military forces are collecting. If the assailant employs similar craft to drive the blockaders away, the defender will bring up larger craft to stiffen his blockading flotillas. The invading force will therefore still be impeded and impeached. The process thus goes on until, if it is not otherwise decided by the conflict of the main fleets at a distance, the contending naval forces of both sides are attracted to the scene of the proposed embarkation, there to fight it out in the conditions involved in the second alternative considered above, conditions which I have already shown to be the least favourable to the would-be invader. In a masterly analysis Mr Julian Corbett has shown that the British defence against a threatened invasion has always been conducted on these lines, that the primary objective of the defence has been the troops and their transports, and that the vigorous pursuit of this objective has always resulted in a decision being obtained as between the main fleets of the two belligerents. That the decision has always been in favour of the British arms is at once a lesson and a warning—a lesson that immunity from invasion can only be ensured by superiority at sea, a warning that such superiority can only be secured by the adequate preparation, the judicious disposition, and the skilful handling of the naval forces to be employed, as well as by an unflinching animus pugnandi. But no nation which goes to war can hope for more or be content with less than the opportunity of obtaining a decision in these conditions. The issue lies on the knees of the gods.

A few illustrations may here be cited. We have seen how in the Beachy Head campaign Tourville, having failed to force a decision on Torrington's fleet in being, could not turn aside with Torrington at his heels and Killigrew and Shovel on his flank to bring over an invading force from France. He was paralysed by that abiding characteristic of French naval strategy which impelled the French naval commanders to fix their eye on ulterior objects and blinded them to the fact that the best way to attain those objects was to destroy the naval forces of the enemy whenever the opportunity offered of so obtaining a decision. Hence their preference for the leeward position in action, their constant reluctance to fight a decisive action, their habitual direction of their fire at the masts and sails of the enemy rather than at his hulls, and in Tourville's case his failure to annihilate Torrington's fleet in being, resulting in the total miscarriage of the schemes for invasion, to be followed by internal insurrection, which, as Admiral Colomb has shown, were the kernel of the French plan of campaign. In the case of the Armada in the previous century, the task of invasion was entrusted to Parma, who had collected troops for the purpose, and vessels for their transport, in the ports of the Spanish Netherlands. But Justin of Nassau kept a close watch outside, and Parma could not move. He summoned Medina Sidonia with the Armada to his assistance, but he summoned him in vain, for the Armada, harassed throughout the Channel, and, as it were, smoked out of Calais, was finally shattered at Gravelines. Precisely the same thing happened in the eighteenth century during the Seven Years' War. Troops and transports were being collected in the Morbihan, but their exit was blocked by a British naval force stationed off the ports. Conflans with the French main fleet was at Brest, and there he was blockaded by Hawke. Evading the blockade, Conflans put to sea and straightway went to release the troops and transports, hopelessly blockaded in the Morbihan. But Hawke swooped down on him and destroyed him in Quiberon Bay, Boscawen having previously destroyed at Lagos the fleet which De La Clue was bringing from Toulon to effect a junction with Conflans.

One more illustration may be cited, and I will treat it at some length, because it presents certain features which give it peculiar significance in relation to current controversies. This is the projected invasion of England by France in 1744. It is, so far as I know, the solitary instance in our naval history which shows the enemy framing his plans on the lines of what is now known as "a bolt from the blue"—that is, he projected a surprise invasion, at a time when the two countries were nominally at peace, in the hope that the first overt act of the war he was contemplating might be the landing of his troops on British soil. In 1743, when this project was conceived, England and France were, as I have said, nominally at peace, but troops belonging to both had fought at Dettingen, not in any direct quarrel of their own, but because England was supporting Maria Theresa and France was supporting her enemies. The fleets of both Powers were jealously watching each other in the Mediterranean, a situation which led early in 1744 to the too notorious action of Mathews off Toulon. Nevertheless, until the very end of 1743 no direct conflict with France was anticipated by the English Government.

Yet France was already secretly preparing her "bolt from the blue." She had resolved to support the Pretender's cause and to prepare an invasion of England in which the Pretender's son was to take part, and on landing in England to rally his party to the overthrow of the Hanoverian dynasty. The bolt was to be launched from Dunkirk and directed at the Thames, the intention being to land the invading force at Blackwall. Some ten thousand French troops to be employed in the expedition were sent into winter-quarters in and around Dunkirk, but this aroused no suspicion in England, because this region was the natural place for the left flank of the French army to winter in, and Dunkirk contained no transports at the time. Transports were, however, being taken up under false charter-parties at French ports on the Atlantic and in the Channel, and were ordered as soon as ready to rendezvous secretly and separately at Dunkirk. At first the intention was for the expeditionary force to make its attempt without any support from the French fleet. But Marshal Saxe, who was to command it and knew that the Thames and its adjacent waters were never denuded of naval force sufficient to make short work of a fleet of unarmed transports, flatly declined to entertain this project and demanded adequate naval support for the enterprise. Accordingly a powerful fleet, held to be sufficient to contain or defeat any British fleet that was thought likely to be able to challenge it, was fitted out with all secrecy at Brest and placed under the command of De Roquefeuil. Even he was not told its destination, and false rumours on the subject were allowed to circulate among those who were concerned in its preparation.

So far everything seemed to be going well. The blow was timed for the first week in January, but the usual delays occurred, and for a month or more after the date originally fixed, the expeditionary force and its escort were separated by the whole length of northern France. Yet even before the date originally fixed, England had got wind of the preparations. From the middle of December Brest had been kept under watch, and orders had been issued to the dockyards to prepare for sea as many ships of the line as were available. These preparations were continued, without intermission, until the end of January, the purpose and destination of the armament at Brest still being unknown. Then two alarming pieces of intelligence reached England at the same time. One was that Roquefeuil had put to sea on January 26 (O.S.) with twenty-one sail of the line, and before being lost sight of by the British cruiser told off to watch him, had been seen to be clearly standing to the northward. The other was that Prince Charles, the son of the Pretender, had left Rome and had landed without hindrance in France. This, being a direct violation of the Treaty of Utrecht, was naturally held to give to the sailing of the Brest fleet the complexion of a direct hostile intent. It was on February 1 that these facts were known, and on February 2, Sir John Norris, a veteran of Barfleur and La Hogue, who was now well over eighty years of age, but as the event showed was still fully equal to the task entrusted to him, was ordered to hoist his flag at Portsmouth and to "take the most effectual measures to prevent the making of any descent on the Kingdoms." Norris hoisted his flag on the 6th, and by the 18th he had eighteen sail of the line under his command. Subsequently his force was increased to twenty. Nothing was known of the movements of the French fleet since January 29, when the frigate set to watch it had finally lost sight of it. It was in fact still off the mouth of the Channel, baffled by adverse winds and gales and vainly seeking to make headway against them. If it had gone to the Mediterranean, Mathews off Toulon would be placed in grave jeopardy, and there were some projects for detaching a powerful squadron of Norris's ships to his support. If, on the other hand, it was aiming at the Channel, Norris with his whole force would be none too strong to encounter and defeat it. This was Norris's dilemma, and it was not until February 9 that he learned from the Duke of Newcastle that an embargo had been laid on all shipping at Dunkirk, where some fifty vessels of one hundred and fifty to two hundred tons had by this time assembled. These might at a pinch and for a short transit be estimated to be capable of transporting some ten thousand troops. But an embargo, although clear proof of hostile intent, was not necessarily a sign of impending invasion. It was a common expedient, preliminary to war, whereby you deprived your enemy of ships and men very necessary to his purposes and secured ships and men equally necessary to your own. Hence no strategic connexion could with any certainty be held to exist between the embargo at Dunkirk and the sailing of the French fleet from Brest. On the other hand it was clearly dangerous to uncover the Channel so long as the destination of the Brest fleet was unknown, and, although Newcastle had suggested to Norris that he should divide his fleet and send the major part of it to reinforce Mathews in the Mediterranean, yet Norris strongly demurred to the suggestion, and before the time came to act on it the situation had so far developed as to disallow it altogether. On February 11, Norris received information that a French fleet of at least sixteen sail of the line had been seen the day before off the Start. This convinced him that the French had some scheme to the eastward in hand; and as he had frigates watching the Channel between the Isle of Wight and Cape Barfleur he was equally convinced that the French had so far no appreciable armed force to the eastward of him. Newcastle, however, did not share this conviction. He had received numerous reports of movements of French ships in the Channel to the eastward of the Isle of Wight and other information which pointed to a concentration at Dunkirk. As a matter of fact no French men-of-war were at this time east of the Isle of Wight, and the vessels reported to Newcastle must have been transports making for Dunkirk and magnified into ships of the line by the fog of war. Newcastle, accordingly, ordered Norris to go forthwith to the Downs. Foul winds prevented Norris from sailing at once from St Helen's, and on the 13th, the day before he did sail, he received further information which confirmed his conviction that the French were still to the westward. But Newcastle's orders remained peremptory, and on the 14th he sailed with eighteen ships, and anchored in the Downs on the 17th. There he found two more ships awaiting him, while two others were on their way to join him from Plymouth.

I pause here for a moment to point out that Norris's desire, over-ruled by Newcastle, to remain at Portsmouth was thoroughly well advised. He knew that there was naval force enough in the Thames and the Downs to dispose of any expedition coming from Dunkirk unless it were escorted by the Brest fleet, or by a very considerable detachment therefrom. He was well assured that no such detachment could have eluded the vigilance of his frigates, and he felt that in these circumstances he could better impeach Roquefeuil by lying in wait for him at Spithead or St Helen's than by preceding him to the Downs. How right he was in this appreciation will be seen from a closer consideration of the movements of the French fleet. It was not until February 13 that Roquefeuil received his final orders off the Start. He was directed to detach De Baraille, his second in command, with five ships. These were to go forthwith to Dunkirk and escort Saxe's expedition, while he himself with the remainder of his fleet was to blockade Norris at Portsmouth and defeat him if he could. But Roquefeuil and his council of war found these orders too hazardous for execution. They resolved not to divide the fleet until at least Norris, presumed to be at Portsmouth, had been disposed of. On the 17th, the day on which Norris had anchored in the Downs, they looked into Spithead and persuaded themselves that they had seen Norris there with eleven sail of the line. Judging that the weather was too bad for a successful blockade, Roquefeuil then passed on up the Channel, convinced that Norris was now behind him with too weak a force to be of any effect. Baraille was then sent on with his detachment to Dunkirk, but by this time Saxe had lost heart and declined to sail until Roquefeuil's whole fleet was at hand to escort him.

It never was at hand to escort him, and the expedition never sailed. Roquefeuil, with his fleet now greatly reduced, anchored off Dungeness on the 22nd, and never got any further. What had happened in the meanwhile was this. Norris remained in the Downs, being held there for some time by a gale. He was not unaware of what was going on at Dunkirk, but he hesitated to proceed thither lest the French fleet behind him should be covering another expedition coming from some French port in the Channel. He sent to reconnoitre, however, and on the 21st received information that four sixty-gun ships—these were, no doubt, Baraille's detachment—were at anchor off Gravelines, and there covering the transports at Dunkirk. On the 22nd, Roquefeuil appeared off Dungeness and anchored there. As soon as he knew Roquefeuil's whereabouts, Norris resolved to attack him without delay. The wind, being N.W., was favourable to his enterprise, and at the same time made it impossible for the expedition to leave Dunkirk. Should the wind change before Roquefeuil was brought to action and defeated, Norris held that he was strong enough to detach a force to impeach Saxe and Baraille, and at the same time to give a good account of Roquefeuil. But matters did not exactly turn out in this wise. On the 24th Norris left the Downs, with a light wind from the N.W., and an ebb tide in his favour, making for Dungeness, where Roquefeuil was still lying. His appearance in the offing was Roquefeuil's first information that Norris was to the eastward of him in superior force, and it greatly disconcerted Roquefeuil. He held a hasty council of war and decided to cut and run. By this time the tide had turned and the wind had fallen, so that he could not stir until the tide again began to ebb. Norris, similarly disabled, had anchored some few miles to the eastward, intending to make his attack as soon as wind and tide allowed. But during the night a furious gale from the N.E. sprang up, which drove most of Norris's ships from their anchors, and when daylight came the French were nowhere to be seen. Roquefeuil had slipped his cables, and with the gale behind him was hurrying back to Brest. Norris went after him as far as Beachy Head, but there gave up the chase and returned to the Downs, to make sure that Saxe and Baraille, for whom the wind was now favourable, might find their way barred should they attempt to set sail. The transports, however, were by now in no position to move, nor was either Saxe or Baraille in any mind to allow them to move. They both realized that the game was up. The troops were in the transports, and they suffered greatly in the gale that frustrated Norris' attack on Roquefeuil. But that was merely an accident of warfare. It was not the gale that shattered the expedition, nor did it save England from invasion. On the contrary, while it played havoc with the transports and troops at Dunkirk, it also saved Roquefeuil's fleet from destruction at Dungeness. But, gale or no gale, the transports and troops never could have crossed so long as Norris held on to the Downs. Nor could they have crossed had Norris been allowed to remain at Portsmouth as he desired; for in that case Baraille could not have been detached.

To point the moral of this memorable story, I cannot do better than quote Mr Julian Corbett's comment on it. "The whole attempt, it will be seen, with everything in its favour, had exhibited the normal course of degradation. For all the nicely framed plan and perfect deception, the inherent difficulties, when it came to the point of execution, had as usual forced a clumsy concentration of the enemy's battle fleet with his transports, and we on our part were able to forestall it with every advantage in our favour by the simple expedient of a central mass on a revealed and certain line of passage." We were certainly taken at a disadvantage at the outset, for the "bolt from the blue" was preparing some time before any one in England got wind of it. The country had been largely denuded of troops for foreign enterprises, Scotland was deeply disaffected, the Jacobites were full of hope and intrigue, the Ministry was supine and feeble, the navy was deplorably weak in home waters, and such ships as were available had been dispersed to their ports for refit. Nevertheless with all these conditions in its favour the projected "bolt from the blue" was detected and anticipated—tardily, it is true, and with no great sagacity except on the part of Norris—long before the expedition was ready to start. Surely the moral needs no further pointing.

By these instances, and others which might be quoted, the law seems to be established that in default of an assured command of the sea the fleet which seeks to cover an invasion is drawn by irresistible attraction towards the place of embarkation, and that the same attraction brings it there—if not earlier—into conflict with the superior forces of the enemy. If in the Trafalgar campaign, which I have no space to examine in detail, the law does not seem to operate to the extent that it did in the other cases examined, that is only because the disposition of the British fleets was so masterly that Napoleon never got the opportunity he yearned for of bringing his fleets to the place of embarkation. They were outmanoeuvred beforehand and finally overthrown at Trafalgar.

There is indeed a fourth alternative which has been advanced by some speculative writers, though history lends it no countenance, and it has never, I believe, been taken seriously by any naval authority of repute. I cannot take it seriously myself. It assumes that some naval Power, suitably situated as regards this country, might without either provocation or overt international dispute, clandestinely take up transport—either a comparatively small number of very large merchant vessels or a very large number of barges, lighters, or what not to be towed by steam vessels—might clandestinely put an army with all its necessary impedimenta on board the transports so provided and then clandestinely, and without either notice or warning, send them to sea, with or without escort, with intent to effect a landing at some suitable point on the English coast. The whole theory seems to me to involve at least three monstrous improbabilities: first, a piratical intent on the part of a civilized nation; secondly, a concealment of such intent in conditions wellnigh incompatible with the degree of secrecy required; and thirdly, a precision and a punctuality of movement in the operations of embarkation, transit, and landing of which history affords no example, while naval opinion and experience scoff at them as utterly impracticable. Of course the future may not resemble the past, and naval wars of the future may not be conducted on a pattern sealed by the unbroken teaching of over eight hundred years. But that is an assumption which I cannot seriously entertain.