So far some 400 casualties had been sustained, including 3 officers killed and 8 wounded. Many of the enemy were killed in the assault, or found lying dead in their trenches, and some 100 prisoners had been taken.
In the advance to the Black line after the capture of the Blue line, the character of the fighting changed. Up to this point the attack had been directed against a trench system badly damaged by shell-fire and only thinly held.
From the Blue line onwards the enemy was in greater strength, and his system of defences was mainly composed of isolated fortified farms and of reinforced concrete blockhouses with double walls, cellars, and wide machine-gun loopholes. The Black line had been so seriously damaged by the artillery that it did not in itself present a serious obstacle; on the other hand, the concreted farms and blockhouses were almost intact. These were particularly troublesome between the Black line and the Black support line.
In this phase of the advance the condition of the ground was appalling, the movements of the infantry being seriously handicapped by the mud, which made it impossible for them to move out of a walk.
The order of battle of the troops detailed for the capture of the Black and Green lines from right to left was as follows: 6th Gordon Highlanders, 6th Seaforth Highlanders, 5th Gordon Highlanders, 6th Black Watch.
On the right the 6th Gordon Highlanders reached the Black line with little difficulty. A machine-gun in rear of Ascot Cottage checked the advance for a short time; the infantry, however, hailed a passing tank, which joined in the action, the cottage being carried and twelve Germans being killed or captured.
Similarly the 6th Seaforth Highlanders captured the Black line behind the barrage except in the neighbourhood of Macdonald’s Farm and Macdonald’s Wood. Here a considerable engagement took place. Two platoons, whose real objective was the northern edge of Macdonald’s Wood, first tackled the farm; while a platoon of the 6th Gordon Highlanders, which had been ordered to the Black line to gain touch with the 6th Seaforth Highlanders, realising the situation, joined in the fight and engaged the enemy in Macdonald’s Wood with enfilade rifle and machine-gun fire. Tank G 50 also arrived, and promptly fired six shells into Macdonald’s Farm. These shells, arriving in company with a storm of bullets and rifle grenades, proved too much for the Germans, who surrendered. Seventy prisoners were taken, many dead lay round the farm, and a 4.2 howitzer and two machine-guns were captured.
On other parts of the front of the 6th Seaforth Highlanders between the Black and the Black outpost lines some fighting took place, and much gallantry was displayed. In one instance two privates captured four Germans and a machine-gun which had been firing on their platoon, one of the privates alone killing six Germans in the process. This battalion also cleverly captured Canister Trench, a trench running at right angles to the line of advance. A half-platoon entered it at each end, and then fought along it until they met in the middle, having wiped out its entire garrison.
The 6th Black Watch on the left of the 6th Seaforth Highlanders had severe fighting in clearing the Black and Black outpost lines. Of the battalions engaged on the Divisional front, the 6th Black Watch sustained most casualties, 9 officers and 292 other ranks. This battalion had suffered considerably in the half-hour before zero while lying assembled immediately in rear of the old British front line, and again while waiting for the barrage to move forward from in front of the Black outpost line. In this position the men were swept by a machine-gun firing from Gournier Farm. Accordingly, when the barrage lifted, No. 1 platoon made at once for this farm. By working round its flanks from shell-hole to shell-hole they rounded it up, taking two machine-guns and twenty prisoners, and later a field-gun. By 6.40 A.M. the Black outpost line was captured on the whole battalion front.