Particular attention should be paid to the outward movements of the flanks, for, as the flanks of our own penetrating or attacking force are generally the most vulnerable points, if we can push forward offensive wings on these flanks we shall not only be protecting our own flanks from attack, by giving the enemy no time to attack in, but we shall be protecting our central line of advance as well. The force operating along this central line not only depends for its movement forward on the security of its flanks, but also on the size of the base of operations; the broader this base the more secure will it be, for the one thing an attacking army wishes to avoid is getting into a pocket on the interior of which all hostile fire is concentrated.
Diagrams 13–15
From the above elementary movements can be worked out a whole series of battle formations according to the various arms which are to be employed. The following three were those generally used by tanks from the battle of Cambrai onwards:
(1) An attack against trenches with an artillery barrage (see [diagram 13]).—Three tanks in line at 100 to 200 yards’ interval, followed by infantry in sections, each section forming an independent fighting unit advancing in single file and attacking in line, the whole forming one firing line. Behind this firing line should advance one tank and a certain number of infantry sections as a support. Reserves can be added as necessary.
(2) An attack against trenches without an artillery barrage (see [diagram 14]).—One tank in advance, followed at a distance of 100 to 150 yards by two others at 200 to 300 yards’ interval, and one tank in support. The infantry should be disposed of as before. The advanced tank to a certain extent replaces the artillery barrage and acts as a scout to the two behind, which form part of the infantry firing line.
(3) The field warfare attack (see [diagram 15]).—In the field attack the action of the tanks must be adapted to circumstances. This action falls under three headings:
(i) Moving in front of the infantry firing line.
(ii) Moving with the infantry firing line.
(iii) Moving behind the infantry firing line.