To ensure success, it was therefore considered necessary to provide a barrage sufficiently dense to sweep the whole area to be attacked with shrapnel bullets. However, additional guns could not be spared readily, while attendant circumstances made it imperative that the attack should be carried out without delay. The attack was launched at 4.45 A.M. on 23rd April, and developed into perhaps the most savage infantry battle that the Division took part in. Attacks continued throughout the day, followed by a succession of determined counter-attacks on the part of the enemy. Both sides sustained serious losses, and many positions changed hands several times in the twenty-four hours. The main attack was delivered by the 153rd Brigade, the 7th Black Watch being on the right, the 7th Gordon Highlanders on the left. In rear of these two battalions, the 6th Gordon Highlanders, temporarily attached to the 153rd Brigade, were on the right, and the 6th Black Watch on the left. The plan was for the two leading battalions to seize the Black, Blue, and Brown lines, while the 6th Gordon Highlanders passed through to the Red line. The 6th Black Watch were to consolidate a line running due north from the left flank of the 6th Gordon Highlanders in the Red line. As soon as the infantry moved forward, a heavy machine-gun fire was opened on them, followed in a few minutes by the German artillery barraging the ground in rear of our assembly trenches. The left of the attack at first proceeded satisfactorily. The 7th Gordon Highlanders repeated their success at Beaumont Hamel. Their left company captured the Black line, according to programme, and killed a number of Germans in it; the second wave passed through them and reached the Blue line, though in very reduced numbers. Only five of this company answered the roll at the end of the operations. The right company of the 7th Gordon Highlanders occupied the Black line, and the left platoon of the second wave entered the Blue line. The remainder of this battalion were held up between the Black and Blue lines, where, incidentally, they captured seventy-six prisoners. The 7th Black Watch were held by machine-gun fire in front of the Black line, and could not get forward. On the right the position of the 154th Brigade remained obscure. It is certain that at one time they were well in Roeux Wood and towards Roeux village, as the bodies of Highlanders were found in those places when the Division subsequently occupied Roeux. This brigade also captured the Black line, in spite of considerable opposition, and killed a number of Germans there. The 4th Seaforth Highlanders carried the chemical works, and they held them on the evening of the 23rd; they were also in the Black line just south of the railway.