He later accepted a commission in the 10th Battalion, Yorkshire Regiment, and serving at Albert, close to the Somme on the Western Front, he suffered concussion from an exploding shell.
While recovering, he produced a poetry collection, A Lap Full of Seed, and an anonymous pamphlet, The Right to Live, inveighing against the kind of society that made war inevitable.
[4] Having been granted a further month's home service in January 1918, he wrote to his battalion adjutant asking to be relieved of his commission on the grounds of religious conscientious objection to all war.
Having been dismissed from the Army, albeit without punishment, he was on 29 June 1918 served with notice of call-up as a conscript, but successfully applied to Hampstead Military Service Tribunal for exemption as a conscientious objector.
[5] In July 1918 Plowman gave a positive review in the Labour Leader to Siegfried Sassoon's anti-war poetry collection Counter-Attack.
In addition to the Alephi, Plowman also wrote for the publications The New Age, Peace News, Twentieth Century, Now and Then and the Theosophical journal The Aryan Path.
Other speakers were Steve Shaw, Herbert Read, Grace Rogers, J. Hampden Jackson, N. A. Holdaway (a Marxist theorist and schoolmaster, and a Director of the Centre), Geoffrey Sainsbury, Reinhold Niebuhr, Karl Polanyi, John Strachey, Plowman and Common.