On 8 August 1918, British Empire and French forces attacked German positions east of Amiens. The offensive began at 4.20 am and achieved one of the largest Allied advances on the Western Front during the First World War.

The main attack was made by General Sir Henry Rawlinson’s British Fourth Army, with the Australian and Canadian corps forming its principal striking force. British III Corps attacked to their north, while the French First Army advanced on the southern flank.

The position of the German Army had changed during the previous months. Its spring offensives had gained substantial territory but failed to force a decision. German units had suffered heavy casualties, and the strategic initiative had passed back to the Allies.

The Amiens operation was prepared differently from many earlier offensives. A prolonged preliminary bombardment would have warned the Germans that an attack was coming. Instead, the Allies used artillery techniques that allowed guns to engage known targets without firing ranging shots beforehand.

Troops, tanks and guns were moved into position under strict security. The movement of the Canadian Corps was concealed particularly carefully because German intelligence had learned to associate its presence with major attacks.

When the assault began, heavy mist covered much of the battlefield. More than 2,000 guns supported the offensive, while more than 500 tanks were available to move with the attacking troops. Aircraft provided reconnaissance and support.

The artillery opened suddenly at 4.20 am. Infantry and tanks advanced behind the barrage. Tanks attacked machine-gun posts and other strongpoints that might otherwise have delayed the infantry.

The surprise worked. Australian and Canadian units moved rapidly through the German forward positions. Some German formations resisted strongly, but others surrendered in large numbers as communications and defensive positions broke down.

By the end of the day, Fourth Army had advanced up to about eight miles on parts of its front. The French had advanced about five miles. Fourth Army captured more than 13,000 prisoners and over 300 guns, with thousands more prisoners taken by the French.

The defeat had a serious effect on German morale. General Erich Ludendorff later described 8 August as the ‘black day of the German Army’. His concern was not simply the territory lost but the number of German soldiers who had surrendered.

The Battle of Amiens continued until 11 August. The first day’s pace could not be maintained as tanks failed mechanically, troops moved beyond their original support and German resistance strengthened.

The Allies did not continue attacking the same positions indefinitely. Further offensives were launched elsewhere along the Western Front, forcing the Germans to respond repeatedly. Amiens became the opening operation of the Hundred Days campaign that continued until the Armistice on 11 November.