The British continued their successful minor operations during the succeeding days. On February 20, 1917, New Zealand troops penetrated German lines south of Armentières to a depth of 300 yards, where they wrecked dugouts and trench works. The intense preliminary bombardment which preceded the raid had proved so destructive that the New Zealanders found the German support lines filled with dead. The raid resulted in the capture of forty-four prisoners. In an attack southeast of Ypres the British, advancing on a front of 500 yards, reached the German support line after desperate fighting. They destroyed dugouts and mine shafts and took 114 prisoners, including an officer and a number of machine guns.
The steady pressure of the British on the German positions along the Ancre since the beginning of the month brought results that surpassed Field Marshal Haig's most sanguine expectations. The Germans were forced to abandon their front on the Ancre, escaping to a new line of defenses along the Bapaume ridge. Their retreat covered about three miles and the British were able to occupy a number of German strongholds which they expected to win by hard fighting. Serre, the two Miraumonts, and Pys were occupied without a struggle. The Germans succeeded in saving their guns during the retirement, but were forced to destroy ammunition dumps and military stores. In the night of February 24, 1917, British troops, advancing south of Irles and toward Warlencourt, occupied the famous butte which had been the scene of intense fighting in the previous month.
The foggy, misty weather which prevailed at the time in this region had greatly facilitated the German retreat, as the keen eyes of the British airmen were unable to study their movements. It was surmised that some important operation was under way owing to the reckless expenditure of shells which had been going on for some days. The Germans were shooting up stores of ammunition which they found impossible to take with them in their retreat.
During February 25-26, 1917, the British continued to harass the retiring Germans, pressing forward over the newly yielded ground and forcing back the rear guards of the enemy. In these actions the Germans depended chiefly on their heavy guns mounted on railway trucks, which in case of necessity could be rushed away at the last moment.
Early in the morning of February 26, 1917, heavy explosions were heard in the direction of Bapaume, where the Germans were engaged in destructive work to prevent the British entry. Along their lines of retreat large trees had been felled across the roads, forming lofty barriers, on the other side of which great mine craters had been opened up.
Despite desperate rear-guard actions, and the strenuous efforts made by the Germans to hinder the advance, the British continued to press forward. The village of Ligny about a mile and a half west of Bapaume was occupied, as well as the village of Le Barque. North of the Ancre the western and northern defenses of Puisieux were wrested from the Germans.
On February 27, 1917, the British pushed forward all along the eleven-mile line stretching from south of Gommecourt to west of Le Transloy. The British objective at this time was a crest overlooking the high ground running between Achiet-le-Petit and Bapaume. At every stage of the British advance fresh evidences were found of the German destructive methods before retiring. The carefully built dugouts which they had so long occupied had been reduced by explosives to heaps of rubbish.
The Germans had left certain bodies of men behind with machine guns to hinder the British pursuit. As they had carefully chosen their positions they were enabled to work considerable damage. The British had encounters with some of these outposts on the 27th in the neighborhood of Box and Rossignol Woods. The Germans, having found that their machine-gun fire did not restrain the advance, tried a shrapnel barrage which proved more effective, but only delayed the pursuers for a short time.
The British troops were so elated over the fact that the Germans were retreating that they made light of the ingenious obstacles thrown in their way. The great advance continued, the British occupying Rossignol Wood, Rossignol Trench, and considerable ground to the northeast of Puisieux. The latter place was partly occupied by Germans who fought as if determined that the British should pay a high cost for possession of the village. The British had worked their way into a corner of the line, and other parties were engaged in driving out the defenders, who fought from house to house.
Southeast of the village the British line was being pushed out above Miraumont and Beauregard Dovecote. The Germans in the Gommecourt salient shelled Miraumont and bombarded the neighborhood with high explosives in reckless fashion as if eager to consume their supplies.