On September 25, 1915, following a four-day artillery bombardment along a six-and-a-half-mile front, British forces launch an attack on German positions at Loos, Belgium, beginning the Battle of Loos.
The British attack at Loos, led by Sir Douglas Haig, commander of the 1st Army of the British Expeditionary Force (BEF), comprised half of a simultaneous Allied offensive begun in two separate regions: as the British proceeded at Loos, the French attacked the German lines at Champagne and at Vimy Ridge in the Arras region of France. Aimed at relieving Russian distress on the Eastern Front by diverting German resources, the ambitious joint offensive counted on superior numbers—including a 3-1 ratio of French to Germans at Champagne—to overpower the enemy. The French commander in chief, General Joseph Joffre, later calculated that 54 French and 13 British divisions went into action along a total front of 90 kilometers.
Despite Allied numerical superiority, the Germans were able to successfully defend their positions against both the British and the French, aided by a second line of trenches and weapons they had constructed five to six miles behind the front lines, shielded from the enemy artillery and out of range of observation. Joffre, for one, tried to justify the offensive’s lack of progress, proclaiming that "We shall kill more of the enemy than he can kill of us." This rationale of attrition would be invoked often throughout the rest of the war, on both sides of the lines. In this case, however, German casualties during the offensive totaled only 60,000, while combined Allied casualties reached a quarter of a million.
At Loos, the British employed poisonous gas for the first time in the war, releasing some 150 tons of chlorine from over 5,000 gas cylinders across no-man’s land. The gas failed, however, to reach the German trenches and inflict any significant damage. By the time the attacks were called off, death tolls at Loos exceeded those of any previous battle: of the nearly 10,000 British soldiers who attacked, 385 officers and 7,861 enlisted men were killed. Haig blamed the BEF’s commander in chief, Sir John French, for failing to commit reserve troops in time to aid the 1st Army at Loos. Invoking this failure, and using his influence with King George V, Haig managed to get French recalled and himself elevated to the position of commander in chief in December 1915.