The massive Allied offensive began at 7:30 a.m. on July 1, 1916, when 100,000 British soldiers poured out of their trenches and into no-man’s-land. During the preceding week, 250,000 Allied shells had pounded German positions near the Somme River, and the British expected to find the way cleared for them. However, scores of heavy German machine guns had survived the artillery onslaught, and the invading infantry were massacred. By the end of the day, 20,000 British soldiers were dead and 40,000 wounded. It was the single heaviest day of casualties in British military history.
After the initial disaster, Haig resigned himself to smaller but equally ineffectual advances, and more than 1,000 Allied lives were extinguished for every 100 yards gained on the Germans. Even Britain’s September 15 introduction of tanks into warfare for the first time in history failed to break the deadlock in the Battle of the Somme. In October, heavy rains turned the battlefield into a sea of mud, and on November 18 Haig called off the Somme offensive after more than four months of slaughter.
Except for its effect of diverting German troops from the Battle of Verdun, the offensive was a miserable disaster. It amounted to a total gain of just 125 square miles for the Allies, with more than 600,000 British and French soldiers killed, wounded, or missing in action. German casualties were more than 650,000. Although Haig was severely criticized for the costly battle, his willingness to commit massive amounts of men and resources to the stalemate along the western front eventually contributed to the collapse of an exhausted Germany in 1918.