White Feather Symbol
During World War I, conscientious objectors were seen as cowards and would find white feathers thrust at them whilst out and about or pinned to their door; sometimes a white feather would be received in the mail anonymously. This was a symbol of cowardice, and also a symbol that the recipient was being viewed as a coward in the community.
Siegfried Sassoon Allegory
The character of Viscount Abercrombie is seen as allegorical, with Abercrombie allegorizing the real life Sassoon. Both men were initially gung-ho leaders who believed passionately in the war effort. Both began the change their opinions when they saw young men being used as cannon fodder, inept generals, and poor strategy. Both began also to reflect their views in their poetry, for which they are both known before the war begins. Both also spend time in a military hospital under the care of a renowned psychiatrist.
Shell Shock Symbol
Shell shock is a symbol of cowardice and desertion to Captain Shannon and to many of his ilk. It is not considered a genuine medical issue, or a genuine psychological one, but is seen more as a pretense that will enable a man to be sent home from the front. To Captain Shannon anything short of running the enemy and committing suicide by German soldier is symbolic of cowardice.
Detective Work Symbol
When Kingsley agrees to go to Flanders to investigate Abercrombie's murder, it offers redemption for him because it is seen as a symbol of his realizing that he was in the wrong to refuse to fight for King and Country. He is obeying a "call up" of another kind, being sent to the battlefield, and undertaking a duty that the Home Office have asked him to undertake. It is a symbol to society at large that it is possible for a conscientious objector to see the error of their decision to refuse to obey the call to arms, and that eventually everyone comes around to see the war effort as something that they are obliged to participate in.
