On March 25 two companies of the 10th Tank Battalion came into action at Achiet-le-Grand and Achiet-le-Petit. At the first-named village, with the 42nd Division, one of these companies attacked the enemy, who, in large numbers, had broken through near Bapaume, and delayed his advance for several hours. By this date no fewer than 113 Lewis-gun groups had been posted in the La Maisonette—Chaulnes, Bray and Pozières—Contalmaison—Montauban—Maricourt areas, and during the night twenty more were sent out to hold the crossings over the river Ancre between Aveluy and Beaucourt. At this time Grandecourt and Miraumont were already in the enemy’s hands and the position was most precarious. These groups held these crossings for several days and inflicted heavy casualties on the enemy each time he attempted to force a passage.
March 26 is an interesting date in the history of the Tank Corps, for, on the afternoon of this day, the Whippet Tanks made their debut. Twelve of these machines, belonging to the 3rd Tank Battalion, moving northwards from Bray were ordered to advance through the village of Colincamps to clear up the situation, which was very obscure. About 300 of the enemy were met with advancing on the village in several groups; these were taken completely by surprise, and on seeing the rapidly moving tanks fled in disorder, making no attempt at resistance. The Whippets then patrolled towards Serre and after dispersing several strong enemy patrols withdrew, having suffered no losses in tanks or personnel. This action was particularly opportune, as it checked an enveloping movement directed against Hebuterne at a time when there was a gap in our line.
Plate III
MEDIUM MARK “A” TANK (WHIPPET).
Save for a few minor tank engagements on March 27, 28, 29, 30, and 31, so far as the Tank Corps was concerned, the Second Battle of the Somme had come to an end, and, before closing this chapter, it is of interest to deduce the main lessons learnt from these the first defensive operations the Tank Corps had ever taken part in.
On March 21, tanks were too scattered ever to pull their full weight. To hit with them as they then were distributed was like hitting out with an open hand in place of a clenched fist, and when the blow fell there was no time to hit and simultaneously close the fingers. Out of a total of some 370 tanks only 180 came into action. The continual withdrawal of tanks by infantry formations in place of moving them forwards amongst the enemy resulted in many machines being worn out before they had fired a shot; this was a faulty use of an offensive weapon.
The two main lessons learnt were: firstly, that speed and circuit are the two essentials for an open-warfare machine; and secondly, one which has already been mentioned but which is so important that it is worth mentioning again, namely, that no great Army, such as the Germans massed against us on March 21, can depend on road and rail supply only. Consequently unless these means of supply are supplemented by cross-country mechanical transport, that is, transport which is independent of road and rail, the greatest success will always be limited by the endurance of the horses’ legs. Men without supplies are an incumbrance, and guns and machine guns without ammunition are mere scrap iron. Had the Germans after March 26 been able to supply their troops mechanically across country, there can be little doubt that their advance would have been continued, for we could not have stopped it, and they might well have won the war. Fatigue may stop an advance gradually, but lack of supplies will stop it absolutely—this is the second and greatest lesson of the Second Battle of the Somme, if not of the entire war.