Revisionist historians of the Western Front have demonstratedthat Britain had no alternative but to wage a war of attrition to defeat Germany. However, the effort to assess this process has been neglected in the historiography. This article explores British attempts to gauge the success of their strategy of wearing down German manpower. Efforts in London proved unable to supply a convincing answer. Using General Headquarters' dubious estimates from the front, Field Marshal Sir Douglas Haig argued that his strategy was working. Prime Minister David Lloyd George's inability to confound these estimates shaped his decision to permit the Passchendaele offensive.war. 5 Victory would turn on the destruction of the German army and its reserves, the center of gravity for the Central Powers. 6 The strategy undertaken to achieve this end was attrition.Meanings of attrition varied at different times, but all required a large mobilization at home and the ultimate destruction of the German Army. 7 In 1914 and into early 1915 Lord Kitchener, the Secretary of State for War, understood better than most that this would be a long war, and set about raising 'New Armies' composed of volunteers. 8 In the meantime he believed that the destruction of the enemy in battle was a distant objective, and it would be preferable for Britain to switch its attention to more immediately promising theaters. For now, attrition would take place on the Western Front in the form of 'limited operations to grind down enemy strength or to repel German offensives'. 9By the middle of 1915, both sides accepted 'the inexorable of the logic of the war': prolonged attrition was the only way to force a decision. 10 In 1916, Kitchener and General Sir William Robertson, Chief of the Imperial General Staff (CIGS), were certain that a combined attritional offensive with the French army on the Western Front was essential to defeating Germany, and ensuring the continued survival of the Entente. 11 The result was the Battle of the Somme. The heavy losses here caused David Lloyd George, Prime Minister from December 1916 onward, to seek alternatives to this costly wearing down process. However, there was no other option which promised victory: the German army must be destroyed in battle in order to win the war. The three great attritional battles of 1916 and 1917, the Somme, Arras, and Third Ypres, were part of 'an essential process of wearing out the enemy', and contributed to Germany's ultimate collapse in 1918 following the failure of the German Spring Offensive and the Allies' Hundred Days Offensive. 12 This strategy of attrition imposed new demands on the British state, including the assessment of its own and enemy resources.