During the First World War, Tawney served as a Sergeant in the 22nd Manchester Regiment. He turned down a commission as an officer as a result of his political beliefs, preferring instead to serve in the ranks. He had initially opposed the war on political grounds, however he decided to enlist following reports of atrocities committed during the German Army's invasion of Belgium. He served at the Battle of the Somme (1916), where he was wounded twice on the first day and had to lie in no man's land for 30 hours until a medical officer evacuated him. He was transported to a French field hospital and later evacuated to Britain. The war led Tawney to grapple with the nature of original sin. "The goodness we have reached is a house built on piles driven into black slime and always slipping down into it unless we are building night and day". It also heightened his sense of urgency for meaningful social, economic and political change. In 1918, he largely wrote "Christianity and Industrial Problems", the fifth report (the other four were on more ecclesiastical matters) from a Church of England commission which included a number of bishops. Notable for its socialist flavour, the report "set the tone for most Anglican post-war social thinking".