Soon after dawn on July 1, 1916, British and Commonwealth troops climbed out of damp, muddy trenches in the Somme valley and began to advance across no-man's land towards German positions. This was the biggest Anglo-French attack of the First World War to date, and British commanders were confident that their troops would quickly push the Germans back out of France and perhaps even begin a drive into Germany itself. The tactics they used in planning this battle had changed little since the Napoleonic Wars. After an artillery bombardment, a mass of infantry would move forward to overwhelm the defenses and then three cavalry divisions would exploit the breakthrough and drive deep into German-held territory. The British commander, Field Marshal Douglas Haig, was certain that this battle would lead to a decisive victory. The Germans had been worn down by fighting on other parts of the Western Front in 1915 and the British attacking force was one of the largest bodies of men at arms ever sent on the attack. However, by the time that night fell on that day, 57,000 British troops had become casualties, including more than 19,000 killed, the highest number of British casualties in a single day of combat. What Haig (and most other military commanders on all sides during World War I failed to grasp was that infantry tactics in use for more than a thousand years were no longer viable. That was simply because sending massed infantry formations to attack prepared enemy defensive positions could no longer succeed in the face of machine guns, which could pour a devastating stream of fire on any exposed troops. Sending troops over open ground to attack a defense that incorporated many linked machine gun positions was simply suicidal, and the outcome was carnage on an industrial scale as more and larger attacks during World War I simply caused even larger numbers of casualties.
