September 2 was the date for the main attack by the First Army upon the Drocourt-Quéant line south of the Scarpe, to which all the fighting which has been detailed was but a preliminary. The rôle assigned to the Seventeenth Corps was to co-operate with the Canadians by thrusting forward their left flank so as to gain position for an attack upon Quéant from the north. The Sixth Corps on their right was ordered to attack Morchies and Lagnicourt and then push forward vigorously towards Beaumetz. The First Canadian Division, with Gagnicourt for its objective, was on the immediate left of the Seventeenth Corps. The orders to the Seventeenth Corps were that the Fifty-seventh Division should support the Canadian attack, that the Fifty-second Division should conform to the movements of the Fifty-seventh on its left and of the Third on its right, and finally that the Sixty-third Naval Division, now added to the Corps, should move up in support and improve whatever advantages were gained. At 5 A.M. the barrage fell and the troops moved forward upon one of the critical battles of the war. The grand part played by the Canadians in the north is described elsewhere. The 172nd Brigade of the Fifty-seventh Division advanced splendidly towards the gap which had been formed, a storm of gas shells bursting among their stolid ranks. The leading battalion, the 1st Munster Fusiliers, followed the men of the Dominion through the breach which they had made in the Drocourt-Quéant switch, and then according to plan swung sharply to the right, smashing their way with bomb and bayonet down the whole line of {136} the German position and so clearing the front for their comrades. It was a fine exploit and worthy of the great battalion which carried it out. They were strongly counter-attacked at the moment when, panting and weary, they had reached their full objective, and yet they retained sufficient vitality to drive back the German stormers. Other elements of the 172nd Brigade had worked south on the right of the Munsters, and got forward as far as Possum Lane, so that they formed a useful defensive flank on the left of the Fifty-second Division. Meanwhile the 171st Brigade had advanced directly from Riencourt Ridge and had cleared up the trenches opposite, which were enfiladed by their comrades.