The undermentioned forces were grouped under the command of Field-Marshal Haig:
The British 4th Army (Rawlinson), comprising the 3rd Corps (3 divisions), the Australian Corps (4 divisions), the Canadian Corps (4 divisions), and 3 divisions of British Cavalry, 2 brigades of armoured cars and 1 battalion of Canadian Cyclists in reserve.
The French 1st Army (Debeney), comprising the 31st Corps (4 divisions), 9th Corps (2 divisions), 10th Corps (3 divisions), 35th Corps (4 divisions), and the 2nd Cavalry Corps in reserve.
The Franco-British Attack of August 8, 1918.
These armies attacked on August 8, along a 15-mile front, from the Ancre to the Avre.
"At 4.20 a.m., after three formidable cannon-shots,—the signal for the opening of the attack,—the rolling barrage broke out before the Australian and Canadian troops, who immediately dashed forward. At the same time, the heavy and light tanks, armoured cars and motor-lorries, loaded with supplies and ammunition, set out. At certain points, the cavalry, followed by the artillery and the aeroplanes, guarded or speeded up the advance. The enemy were taken completely by surprise. The troops and staffs were taken prisoners before they realized what had happened. One after another, the villages were surrounded and captured. Forging ahead of the infantry, the cavalry and tanks spread panic everywhere."
The British advanced rapidly in the direction of Rosières, along both sides of the Amiens-Chaulnes railway.
Towards evening, the advanced line passed through Mézières, Caix and Cerisy. Everywhere, except at Morlancourt, north of the Somme, where the enemy resisted desperately, the Germans were routed.