In the British lines the defended village of Ecurie, about 100 metres above sea-level, afforded a good view of Thelus and of the enemy’s defences at a distance of from 400 to 500 yards behind his front line. Observation of his front-line trenches could in most places only be obtained from observation posts in the forward area.
The relief of the French 23rd and 24th Divisions of the XIIme Corps d’Armée was completed by 14th March. It was carried out during a blizzard of great severity, which continued for forty-eight hours. During this period the troops could do no more than remain where they had been placed by their guides, or misplaced as the case might be. During the relief and, in fact, until the blizzard abated, officers and men had only a hazy idea as to where they actually were. Similarly commanders were ignorant of the position of their troops. All three infantry brigades were in the line—the 154th Brigade on the right in the vicinity of Roclincourt, the 152nd in the centre, and the 153rd on the left.
When the weather cleared, it was found that the Division had taken over from the French an unintelligible tangle of trenches dug in what can only be described as a vast cemetery, in which the earth in many places barely covered the dead.
The sector was also honeycombed with mines from end to end, the enemy apparently being complete masters of the mining situation. In fact, his supremacy in mining had become so complete that, immediately prior to the relief, the French had drawn up a scheme for evacuating the front line except for lightly-held outposts. The plan they had intended to adopt was to recast the scheme of defence and construct amidst the existing network of derelict trenches a new support and reserve line. The scheme had been completed, and was on the point of being put into execution when the Highland Division took over the sector. The Divisional commander decided to continue with this policy. The construction of the new scheme of defences necessitated a vast amount of work, and was only fairly complete three months later when the Division left the sector.
This alteration in the siting of the trenches demanded the construction of an enormous number of dug-outs. It soon became evident that without these the daily casualty list must be heavy. Not only was the artillery activity considerable, but the German had also concentrated in this sector every type of trench-mortar which had been evolved, and was extremely free in his use of them.
The mining was of a more savage nature than had been the case in La Boisselle, and in many instances resulted in serious infantry fighting. The mines were, as a rule, blown by the enemy with two objects. If the breadth of No Man’s Land was not considerable, they were frequently blown with a view to destroying our trenches with their garrisons. If, however, the breadth of No Man’s Land was great, or his system of defensive galleries were good, he would blow his mines in No Man’s Land with a view to occupying them as a line of observation and snipers’ posts. By the frequent blowing of this type of mine, he was able to cover his front with a screen of craters which denied the British observation of his front line, and created for him a chain of commanding mounds along our front.
In some cases, if the crater formed by a mine explosion was some distance from the British front line, no infantry action would follow. If, however, a mine was blown under a British trench, it was usually accompanied by an enemy raid, which was planned to enter our trenches during the confusion caused by the mine and surprise the surviving garrison. If, on the other hand, it was blown in No Man’s Land close to the British front line, it was necessary at all costs to prevent the enemy from occupying it. Thus in the two last cases heavy infantry fighting often occurred. In the latter case, the object of these actions was to prevent the enemy from establishing himself on the crater. If he did so the position was serious, for the crater became a permanent menace to the security of our lines. Where the ground might have been flat, a large hollow mound had now arisen. If the enemy established himself on the British side of the mound (i.e., the near lip, as it was called), he might construct sniping-posts which would dominate the trenches. Should he only establish himself on the far lip, he still was able, by working around the lip of the crater towards the flank, to shoot down into our trenches in enfilade.
It was suggested that the Germans, by some peculiar method of tamping (i.e., packing the explosive in the chamber), used to blow his craters with the far lip higher than the near lip. Thus, if he only established himself on the far lip, the near lip, being lower, did not obscure his view to the front; conversely the view from the near lip, if occupied by the British, was obscured to the front by the higher far lip. Whether his craters were formed in this manner from accident (i.e., the lie of the ground) or from design is not clear. The fact remained that an examination of many craters in the Neuville St Vaast area proved this to be the case.
These crater fights often developed into considerable minor operations involving many casualties. They almost always took place in the dark, and were an unpleasant ordeal for all concerned.