Some 200 miles of broad-gauge track was laid between April and July and a complete series of new defences were built, involving, incredible as it may seem, 5000 miles of trench. Nor were Tanks left out of the scheme of reorganisation. But, alas! owing to the extreme need of infantry reinforcements, and the difficulty of immediately re-arming Battalions which had lost their Tanks during the Retreat, this “reconstruction” all but took the form, not of augmentation, but of diminution. It was proposed to reduce the number of Tank Brigades from six to four. The appearance of enemy Tanks, however, soon quashed this project. Not only had the Corps lost heavily in machines, but the fighting done by the Lewis gun Units had been of a particularly strenuous kind, and several Battalions had sustained such casualties in trained and experienced men as to cause great anxiety at Tank Headquarters. However, the Tank Corps were only in the same predicament as the rest of the British Army, and there was nothing for it but to gather up the bits with as much grace as possible and to start away as quickly as might be on the work of reconstruction. All through May, Mark V. machines were arriving in France at the rate of about sixty a week. Some of the Battalions which had not taken any part in the Retreat had been left in their original areas, in case the Germans should attack, so that we find Battalions (for example of the 1st Brigade) doing “Savage Rabbit” as late as the middle of May. For the most part, however, the Corps was gathered together undergoing intensive training in the Bermicourt area. All Tank Units were to be ready for action--re-armed, re-equipped and re-trained--by August 1. The Central Workshops set to work in early June to prepare sledges for supply haulage, bridges upon which the Whippets could cross wide obstacles, and “Cribs” for the heavy Tanks. There “Cribs” were big hexagonal oaken crates, reinforced with steel, which were an improved and lighter version of the fascines which were improvised for the Battle of Cambrai. Training grounds and workshops hummed with the preparations, and when, in the last days of July, the call came, it was, as we shall see, found possible to launch 400 Tanks at little over a week’s notice.