engine of war ever known. The weaker the naval defence of the threatened country, the more devoutly will it pray the invader may use this device. Where contact with the enemy's fleet is certain, and particularly in narrow seas, as it was in this case, such a course will give the defender all the chances he could desire, and success for the invader is inconceivable, provided always we resolutely determine to make the army in its transports our main objective, and are not to be induced to break our head against its escort.
Where, however, contact is not certain, the invasion over an uncommanded sea may succeed by evasion of the defender's battle-fleet, as it did in the case of Napoleon's invasion of Egypt. But that operation belongs to an entirely different category from that which we are now considering. None of the factors on which the traditional system of British defence is based were present. It was an operation over an open sea against a distant and undetermined objective that had no naval defence of its own, whereas in our own case the determining factors are permanent naval defence, an approximately determined objective, and a narrow sea where evasion by any force of invasion strength is impossible. Napoleon's exploit was in fact nothing more than the evasion of an open blockade which had no naval defence beyond it. The vital importance of these things will appear as we proceed and note the characteristics which marked every attempt to invade England. From such attempts we of course exclude the various descents upon Ireland, which, not being of invasion strength, fall into another class, to be dealt with hereafter.
Since the expedient of forcing an invasion by the strength of a powerful battleship escort has always been rejected as an inadmissible operation, the invader has had no choice but to adopt a separate line for his army, and operate with his fleet in such a way as may promise to prevent the enemy controlling that line. That, in short, is the problem of invasion over
an uncommanded sea. In spite of an unbroken record of failure scored at times with naval disaster, continental strategists from Parma to Napoleon have clung obstinately to the belief that there is a solution short of a complete fleet decision. They have tried every conceivable expedient again and again. They have tried it by simple surprise evasion and by evasion through diversion or dispersal of our naval defence. They have tried it by seeking local control through a local naval success prepared by surprise, or by attempting to entice our fleet away from home waters to a sufficient extent to give them temporarily local superiority. But the end has always been the same. Try as they would, they were faced ultimately by one of two alternatives—they must either defeat our covering battle-fleet in battle, or they must close their own battle-fleet on the transports, and so set up the very situation which it was their main design to avoid.
The truth is, that all attempts to invade England without command of the sea have moved in a vicious circle, from which no escape was ever found. No matter how ingenious or complex the enemy's design, a determined hold on their army as the primary naval objective has always set up a process of degradation which rendered the enterprise impracticable. Its stages are distinct and recurrent, and may be expressed as it were diagrammatically as follows:—
Two lines of operation having been decided on, the invading army is gathered at a point as close as possible to the coast to be invaded; that is, where the intervening sea is narrowest, and where the army's passage will be exposed to interference for the shortest time. The covering fleet will operate from a point as distant as convenient, so as to entice the enemy as far as possible from the army's line of passage. The
defender replies by blockading the army's ports of departure with a flotilla of light vessels capable of dealing with transports, or by establishing a mobile defence of the threatened coasts which transports cannot break unaided, or more probably he will combine both expedients. The first fallacy of the invasion plan is then apparent. The narrower the sea, the easier it is to watch. Pure evasion becomes impossible, and it is necessary to give the transports sufficient armed strength by escort or otherwise to protect them against flotilla attack. The defender at once stiffens his flotilla defence with cruisers and intermediate ships, and the invader has to arrange for breaking the barrier with a battle-squadron. So weak and disturbing a position is then set up that the whole scheme begins to give way, if, that is, the defender has clung stubbornly to the strategy we always used. Our battle-fleet refused to seek out that of the invader. It has always held a position between the invader's fleet and the blockaded invasion base, covering the blockade and flotilla defence. To enable a battle-squadron to break our hold and to reinforce the army escort, the invader must either force this covering position by battle, or disturb it so effectively as to permit the reinforcing squadron to evade it. But since ex hypothesi he is trying to invade without securing the command by battle, he will first try to reinforce his transport escort by evasion. At once he is faced with new difficulty. The reinforcement entails dividing his fleet, and this is an expedient so vicious and disturbing to morale, that no invader has ever been found to risk it. And for this reason. To make evasion possible for the detached squadron, he must bring up the rest of his force and engage the attention of the enemy's fleet, and thus unless he is in very great superiority, and by hypothesis is not—he runs the hazard of having his two divisions beaten in detail. This method has sometimes been urged by Governments, but so loud have been the protests both from the fleet and the army, that it has always been dropped, and the invader finds himself
at the end of the vicious circle. Unable to reinforce his transport escort sufficiently without dividing his battle-fleet, he is forced to bring his whole force up to the army or abandon the attempt till command shall have been secured by battle.
Thus the traditional British system has never failed to bring about the deadlock, and it will be observed it is founded on making the invading army the primary objective. We keep a hold on it, firstly, by flotilla blockade and defence stiffened as circumstances may dictate by higher units, and secondly, by battle-fleet cover. It is on the flotilla hold that the whole system is built up. It is the local danger to that hold which determines the amount of stiffening the flotilla demands, and it is the security of that hold which determines the position and action of the battle-fleet.
A few typical examples will serve to show how the system worked in practice under all kinds of conditions. The first scientific attempt to work on two lines of operation, as distinguished from the crude mass methods of the Middle Ages, was the Spanish enterprise of 1588. Though internal support from Catholic malcontents was expected, it was designed as a true invasion, that is, a continuing operation for permanent conquest. Parma, the military commander-in-chief, laid it down that the Spanish fleet would have not only to protect his passage and support his landing, but also "to keep open his communications for the flow of provisions and munition."