When moving with the infantry firing line, which will generally be the most suitable formation to adopt, tank sections should form mobile strong points or bastions, which will not only reduce the number of infantry required for the firing line, but which will be able to bring oblique and cross fire to bear in front of the advancing infantry. In order to reduce the human target as much as possible without reducing fire effect, Lewis-gun sections should freely be used to cover by fire the intervals between tank sections. These Lewis-gun sections should be followed by rifle sections which, directly opposition is broken down by the tanks and the Lewis gunners, should move rapidly forward several hundred yards in front of the tank and infantry firing line, forming to it a protective screen of sharpshooters. This formation should then be maintained until the rifle sections get hung up, when the tank and Lewis-gun firing line should pass through them to renew the attack, the rifle sections forming up in support in rear. Curiously enough this formation resembles very closely that generally adopted by the Roman Velites and Hastati (riflemen), Principes (Lewis gunners), Triarii (tanks), and Napoleon’s Light Infantry (riflemen), Infantry of the Line (Lewis gunners), Old Guard and Heavy Cavalry (tanks).
As an infantry attack depends on the following principles—the objective, the offensive, security, mass, economy of force, surprise, movement, and co-operation—so does a tank attack. The tank must know what it is after, it must act vigorously, it must be protected by artillery just like infantry, it must attack in mass, that is in strength and numbers, but not, necessarily, all in one place; it must surprise the enemy, move as rapidly as it can, and work hand in glove with the other arms. On the application of these principles to the conditions which will be met with will depend the success or failure of the tank attack.
The first condition to inquire into is the position of the objective; is the ground leading up to it suitable for tank movement, is the country on the flank of such a nature as to permit of offensive wings being formed? The second is the position and number of the enemy’s guns; can these be controlled by counter-battery work or smoke; how will they affect the lines of approach and their selection? The third is the number of subsidiary objectives before the final one is captured. The fourth is the “springing off” position of our own infantry, and the fifth is, how can the enemy be surprised? These five questions being satisfactorily answered, the normal procedure is to divide the whole tank force into a main body and two wings; to take these three forces and to divide each up into as many lines of tanks as there are objectives to be attacked; to divide each objective up into tank attack areas according to the number of tactical points each contains. Provided the enemy does not possess tanks himself, or a sure antidote to their use, which the Germans never did possess, a well-considered and mounted tank, infantry, artillery, and aeroplane attack is the nearest approach to certainty of success that has ever been devised in the history of war. No well-planned extensive tank attack has in the past ever failed, and each one has resulted in more prisoners having been captured than casualties suffered. These are historic facts and not mere pæans of praise; they, consequently, deserve our most careful consideration when eventually we plan and prepare for the future.
CHAPTER IX
THE BATTLE OF ARRAS
The great battles which opened the Allies’ 1917 campaign on the Western Front were the direct outcome of two main causes:
(i) The strategical positions of the opposing Armies resulting from the battle of the Aisne in 1914.
(ii) The tactical position of the same Armies resulting from the battle of the Somme in 1916.
The former placed nine-tenths of the German Army in the west, in a huge salient Ostend-Noyon-Nancy; the latter a considerable portion of that Army in a smaller one, Arras-Gommecourt-Morval. The former offered possibilities for the Allies to get in a right and left hand blow on two of the main centres of the German communications—Valenciennes and Mézières; the latter a right and left hand blow in the direction of Queant against the northern and southern flanks of the German Sixth and First Armies.