Denis Argent brought his keen reporter's eye to the unusual Army unit in which he worked until the middle of the war – the Non-Combatant Corps (NCC). Non-combatants were men who had successfully convinced a Tribunal that they were conscientious objectors who were willing to serve their country but who did not want to bear arms. The Tribunal then recommended that the man's name be removed from the register of conscientious objectors ‘with the proviso that he should be called up for non-combatant duties only’.

Denis himself developed pacifist convictions during the 1930s. He was an active member of the Peace Pledge Union, occasionally attended meetings of the Fellowship of Reconciliation, an anti-war organisation, and at least once gave a talk at a meeting of pacifists (7 November 1939). He was content to make a contribution to his nation's defence. He did not want to kill but he did want to serve. On 26 January 1940 he attended his Tribunal at Southwark County Court – his preference was to serve in the Royal Army Medical Corps and he had prepared for this by taking training in first aid – and in late April 1940 he was called up for service in the newly created first Non-Combatant Corps. After initial training in Norfolk, he served as a medical orderly in Wales, first in Barry Docks, Glamorganshire, and from October 1940 at a rather remote camp several miles outside Haverfordwest, Pembrokeshire.

His position as a medical orderly allowed him plenty of contact with all members of the unit, with members of the Pioneer Corps (who provided military labour), and, less frequently, with members of nearby combatant units. His time was also flexible enough that he was able to fulfil his determination ‘to watch everything with a cool reporter's eye’ (17 August 1940) – a goal that, as his diary reveals, he often achieved. He thought that ‘the whole atmosphere of this Conchie Corps as a whole is different from that of any other conscript unit’ (17 March 1941). The newly formed company was, he estimated, originally about 200 strong; virtually all ‘registered by Tribunal for non-combatant service’, including many like himself who had been recommended for the Royal Army Medical Corps. The company was placed under NCOs of the Auxiliary Military Pioneer Corps, all or almost all of whom were veterans of the First World War.