Cavalry Corps : 1st, 2nd and 3rd Cavalry Divisions

III Corps : 12th Division, 18th Division, 58th Division, and the 130th and 131st Infantry Regiments of the 33rd American Division.

Canadian Corps : 1st, 2nd, 3rd and 4th Canadian Divisions, and 32nd Division

Australian Corps : 1st, 2nd, 3rd, 4th and 5th Australian Divisions, and 17th Division

This action includes the subsequent Actions round Damery, fought by the four Canadian Divisions, on 15 - 17 August.

Note : the American 131st Regiment transferred to the Australian Corps on 9 August.

Henry Rawlinson, in command of Fourth Army, chose to employ nine Divisions supported by 400 tanks in the initial assault. Great efforts were made to maintain secrecy, especially in concealing the presence of the Canadian Corps, which had not been involved in fighting for some time. Some Canadian units were sent to Ypres, and Canadian wireless traffic was maintained in Flanders to deceive the enemy.

On 29 July, formal operation orders were issued, which required the line Hangest - Caix - Harbonnieres - Méricourt to be achieved. The French units would operate south of the Amiens - Roye road, the British north. The 5th Australian Division carried out a successful minor operation south of Morlancourt, before the Australian Corps extended 7,000 yards southward, taking over the front that would actually be the start position for the Canadians. The latter arrived in the rear areas by 4 August. The strength of the Fourth Army increased to over 441,000 men. It also had the benefit of the field artillery of the 25th Division and the 5th Canadian Division, and 13 additional Brigades of Heavy artillery. The Tank Corps provided 342 heavy tanks, 72 Whippets and 120 supply tanks.

Behind the Fourth Army front, immense preparations were made on the lines of communication, with new railways, dumps, water supplies and many other preparations being made. Labour work would halt at zero and all men be in readiness to move up behind the advance to put roads in a state of repair. Two Casualty Clearing Stations were made available to each Corps, and three other for specialist cases made ready, along with ten Ambulance Trains ready to move casualties towards the coast. Prisoner of War cages were also built.

During the nights when the attacking units assembled, German gas shelling was persistent, and on 7 August 25 tanks were destroyed by a heavy enemy bombardment. Soon after dawn on 6th August, a heavy raid on units of the 58th and 18th Divisions near Morlancourt led to a loss of ground 800 yards deep, with some 236 men being taken prisoner. None gave anything away about the imminent attack. Zero hour was fixed for 4.20am on 8 August.

The German command received reports of additional noise of movement and even of 100 British tanks seen in the vicinity of Moreuil, but did nothing. On 4 August, Ludendorff said that there was "nothing to justify this apprehension, provided our troops are vigilant and do their duty".

8 August 1918 Canadian Corps: The Corps covered the area between the Amiens - Roye road, and the Amiens - Chaulnes railway line. 3rd Canadian Division on the right, attacking across the ravines of the Luce valley, achieved all objectives by 11am, despite heavy fighting near Hangard cemetery. Only 8 of the machines of the 5th Battalion, the Tank Corps survived the action, out of 19. 1st Canadian Division on their left captured Aubercourt before being involved in heavy fighting for Hangard Wood. A little further on at Morgemont Wood, the enemy broke and ran. By 11am the Division was in Cayeux, with 11 of 18 tanks. The 2nd Canadian Division followed a 'magnificent' barrage and captured Marcelcave with surprising ease, and by 9.20am was in Wiencourt. Only 4 of their tanks were lost. By noon the Santerre plateau was quiet, with masses of men and equipment moving forward; the leading infantry were already beyond the cover of their own field artillery. Few German guns were still firing. On the extreme right, the Canadian Cavalry Brigade moved up to cover the flank on the Amiens - Roye road. They captured Beaucourt but ran into resistance at Le Quesnel; other units entered Cayeux Wood, and moved beyond Caix and Guillaucourt. The 4th Canadian Division moved up and passed through the assault units, advancing the line further. By day's end the Corps had captured all its objectives with the exception of ground near Le Quesnel.

Australian Corps: The Corps covered the area between the Amiens - Chaulnes railway, and the Somme. 2nd Division attacked on the right, with 23 tanks. They advanced into feeble opposition, and had difficulty only as a result of the bad visibility. They reached first objectives by 7.10am, having lost 4 tanks to mines and direct shell hits. The 3rd Division attacked along the Somme valley, with 24 tanks, in very thick fog. Near the river, the 11th Brigade had to move through deep mud, reeds and other undergrowth. The advance could not keep up with the barrage in such conditions, although this risk was negated by good work by the tanks in quelling enemy strongpoints, and in feeble and wild fire by the Germans. By 7am, the two attacking Brigades were on their objective, having captured many hundreds of prisoners and guns. The 54th and 4th Australian Divisions passed through as planned at about 8.20am. By 1.30am the Corps had captured all its objectives, except at the flanks with the neighbouring Corps. A strong feature of the second part of the advance was the coordination of infantry and artillery with Cavalry units, tanks and armoured cars. The Royal Air Force also played a large part, especially in harassing retreating German units.

III Corps: The British Corps had the difficult objective of capturing the high ground North of the Somme, to cover the flank of the advancing Australians. In terms of distance, this was a more modest objective than those set for South of the river, but the ground was far more complex and difficult, especially for tanks. All Divisions of the Corps had been heavily depleted during the year, and were now largely composed of young soldiers, with relatively few experienced NCOs and officers. The 58th and 18th Divisions attacked, and despite thick fog and the very recent arrival in position of some of its units, at first advanced easily. By 9.30am the 58th had captured Sailly Lorette and had an excellent view of Chipilly, 2500 yards over the next spur. On the left the 18th Division, attacking without the aid of tanks, ran into strong resistance.

The total British casualties amounted to just over 22,200 of all ranks, killed, wounded and missing. Cavalry Corps losses were 887 (of which 101 died); III Corps 6,250 (4,012); Canadian Corps 9,074 (2,266), and Australian Corps 5,991 (850). German losses were approximately 74,000.

'The Black Day of the German Army': First Quartermaster-General Ludendorff The material losses and ground lost would hardly seem to justify Ludendorff's gloomy summary. However, he was referring to the fact that whole units had surrendered to very small forces; that officers seem to have lost control and the confidence of their men. He 'could no more even think of long and successful resistance in the attrition of defensive battles'. It was the beginning of the end for Germany.

Nine assaulting Divisions; the same as 1st July 1916, on a similar frontage. A great victory, planned and executed most professionally and thoroughly - and all but forgotten.

By August 1918, the British army was confident. It had defeated the great German attacks, and it was believed that the Kaiser had shot his bolt. The ranks were by now largely composed of young men, mostly conscripts. After the war, it was the Germans who composed mythology: that the 400 tanks in thick fog had overwhelmed them.

Just before the battle, out-of-touch British CIGS Henry Wilson issued a memorandum on "British Military Policy 1918-1919", in which he suggested conserving forces for an assault to begin on 1 July 1919. But both before and especially after this great success of 8 August and succeeding days, it was Douglas Haig that began to sense the possibility of victory in 1918.