The advance of the 19th March covered a depth of nearly 10,000 yards, and as it was achieved with very little fighting it seems evident that the Germans' preparations for withdrawal had been conducted with great skill. From the time when they had left their original line at Monchy they had almost entirely eluded close touch with our pursuing columns, which were never able to harass their retirement to any useful extent. Very little war material fell into our hands, and it seems possible that valuable hours were lost on the 17th before the order to follow up the retirement reached battalions in the line.
The pursuit of the Germans was rendered exceedingly slow and arduous by the unspeakable destruction which met our advancing columns at every step. Cross roads had been mined and vast craters forced all wheeled traffic to deviate on to the sodden fields adjoining. Trees had been felled across the roads and added to the impediments to the advance of our artillery. Everywhere the Germans had committed wanton destruction—young fruit trees were ringed, crops were burnt wholesale, and every sort of live stock had been driven before them in their retreat. The aspect of the villages was most peculiar. At a distance they appeared to be untouched, and the red roofs of the cottages showed nothing unusual. On a closer approach, however, they were found to be ruined and the walls knocked down so that the roofs had subsided intact to the ground. Furniture, too heavy to be moved, had shared in this destruction, and its débris was lying shattered among the heaps of brick and stone. Yet further abominations had been invented, and a series of ingenious "booby-traps" were discovered in the shape of common articles such as shovels and helmets. These were left lying about in places where they were likely to be picked up by our troops, and being connected with bombs and even large mines caused explosions when they were touched.
By noon on the 19th March the 2/1st Londons had established themselves after some opposition from machine-gun fire on the line between Boiry-Becquerelle and Boyelles, in touch with the 46th Division in Hamelincourt; but further efforts to advance from this position towards St Leger, which was the objective for the day, were effectually stopped by heavy enemy shell and machine-gun fire.
Meanwhile the 2/4th Londons were once more moved forward, leaving Ransart at about 3 p.m., and by 5.30 had advanced to the line of the Boyelles-St Leger Railway on the right of the 2/1st Londons.
The 173rd Brigade now occupied the whole of the 58th Divisional front, being in touch with the Division on its right and its left joining the 30th Division who were facing Henin-sur-Cojeul. The line occupied by the 2/4th and 2/1st Londons formed a marked re-entrant in the British line, overlooking a valley which runs in a northerly direction from St Leger to Henin-sur-Cojeul. The enemy had apparently deployed on the further side of this valley and was holding the line of the Henin-Croisilles Road. Opposite the right flank of the 2/4th Londons he had for the moment considerable advantage of ground over us, as our line was dominated by a hill which protected Croisilles from observation. The following day the Brigade consolidated itself in this position, Brigade Headquarters moving forward to Boiry-St Rictrude, which was also occupied by the 2/3rd Londons in Brigade reserve, while the 2/2nd Londons moved into close support in Boisleux-au-Mont.
The line held by the Brigade extended from Judas Farm near St Leger, where it was in close touch with the Division on the right, in front of Boyelles and Boiry-Becquerelle to the north branch of the Cojeul River. North of the river the line was continued by the 30th Division, who were endeavouring to force the villages of St Martin and Henin.
The Battalion had pushed outposts beyond its main line on the railway to the Boiry-St Leger Road, but all attempts to continue the general advance beyond this line were frustrated by the heavy machine-gun and shell fire with which the enemy sprayed the forward slopes of the ridge down which the advance was to be made. At the same time signs were not wanting that his withdrawal had not reached its limit, for fires were observed in Henin and Croisilles which indicated that the systematic destruction which hitherto had been the prelude to his retirement was proceeding with unabated vigour.
On the 21st the 2/4th Londons were relieved by the 2/3rd in the right subsector and withdrew to Boiry-St Martin in reserve. For three days the Battalion remained here under conditions of extreme discomfort. The weather was exceptionally severe and the ground was covered with snow, while the open and bare hillsides were swept by biting winds. Billets were non-existent owing to the total destruction of the village, so that the change from the front line to reserve brought very little of rest or easier conditions. Indeed throughout this period of the advance the terrible exposure proved a far more serious enemy than the Germans themselves, and the casualties caused through it were five times more numerous than those caused by wounds.
The Hindenburg line was now within measurable distance, and the salient previously held by the enemy being almost entirely flattened out it was found possible to withdraw several divisions now in action. This was the more desirable not only for the provision of as many reserve divisions as possible for the impending offensive against the Vimy Ridge, but also for the tasks of rendering the devastated region covered by the advance habitable to our forces, of repairing the ruined roads, and of bringing forward the supplies of material necessary for further operations. One of the important gains of the advance was the reopening of direct lateral communication between Arras and Albert. With their usual thoroughness the Germans had completely destroyed the railway connecting these two towns, the track being torn up and the bridges demolished; and the complete reconstruction of it presented one of the most pressing necessities in the organisation of the new defences.