He was posted to France on the 6th October 1914. He and a another Stevenage man, Harold Holdron were to be killed in the most renowned battle of all, the first day of The Battle of the Somme, where the British army suffered some 60,000 casualties. He fell when his battalion was involved in the assault on Mametz. The attack began at 07.27am with the Battalion being given the task of capturing a series of German trenches named; Danube Trench, Apple Alley, Shrine Alley and Hidden Lane. The troops met with heavy machine gun fire from the village of Mametz as well as from Fricourt, which was to their left. Eventually, they managed to achieve all their objectives but had suffered 343 casualties, including William Chamberlain. He is buried in the Dantzig Alley British Cemetery, Mametz, France.