The advancing British troops in the south this day were beginning to threaten Puisieux, the possession of which would lay open to attack the Bucquoy Ridge to its north. It was clear that with British forces on the Bucquoy Ridge the German reserve lines of defence and gun positions about Adinfer Wood (which supported the lines now opposite the 173rd Brigade) must either retreat precipitately or run a serious risk of being cut off. Requests for information from Brigade consequently became more and more insistent, and information was passed to the Battalion that the lines opposite had actually been evacuated. Officers' patrols under 2/Lieuts. A. G. Croll, A. M. Duthie, T. J. Bell and D. S. Boorman, which covered No Man's Land, especially in the vicinity of the Blockhouse and the Talus on the nights of the 24th and 28th, however, elicited unmistakable signs of occupation of the German defences. But the desultory nature of the enemy's machine-gun fire, and of his shell fire from the direction of Adinfer Wood, the marked decrease in the number of Véry lights put up by him at night and the constant sounds of transport moving on the roads in rear of his lines all provided indications that his retirement could not long be delayed. The patrols frequently heard working parties hard at work in rear of the enemy's lines, and it afterwards transpired that these were busily engaged in mining the roads over which our advancing troops must pursue the German retreat. It had long been known that the enemy was hard at work on a highly fortified defensive line which left his front defences at Arras and ran in a south-easterly direction in front of Cambrai to near St Quentin. This line, the famous "Hindenburg" line, was roughly parallel to that now occupied by our advancing troops in the south and some eight miles distant from it. Reports from British airmen showed that the Hindenburg line was now the scene of feverish activity on the part of the enemy, and this information seemed to confirm the probability indicated by the results of our patrolling that the relinquishment of the Monchy-Arras line was imminent. A most unfortunate incident occurred on the night of the 28th February, when a strong patrol under 2/Lieut. R. K. Caparn returning to our lines was fired upon by the sentries who apparently had failed to grasp the prearranged signal, with the regrettable result that 2/Lieut. Caparn was very seriously wounded and L./Corpl. Warren, Ptes. Anderson and Vickery were killed. On the morning of the 2nd March the Battalion was relieved by the 2/2nd Londons and withdrew to Divisional reserve in billets at Basseux and Bailleulval. Three days' training ensued, followed by a move on the 6th to Humbercamp.