Ritson's career as an inspector of mines was placed on hold when he was called for active service with the outbreak of the First World War, where as a former soldier he was recalled to the Durham Light Infantry serving in the Territorial Army.
Ritson remained at Royal School of Mines until 1952 when he was succeeded by J.C. Mitcheson, and in 1955 he was made a fellow of Imperial College in recognition of his work [REF].