The Great War was indeed a world war. Imperial powers like Great Britain drew on their far-flung empires not only for resources but also for manpower. This essay examines one important (though still inadequately studied) aspect of British wartime exigency, the voluntary and coerced participation of the British Empire's coloured subjects and allies in military operations on the Western Front. With the exception of the Indian Army in the first year of the war, that participation did not include combat. Instead coloured troops, later joined by contract labourers, played major roles behind the lines. From 1916 onwards, well over a quarter million Chinese, Egyptians, Indians, South Africans, West Indians, New Zealand Maoris, Black Canadians, and Pacific Islanders worked the docks, built roads and railways, maintained equipment, produced munitions, dug trenches, and even buried the dead. Only in recent years has the magnitude of their contribution to Allied victory begun to be more fully acknowledged. Yet the greatest impact of British labour policies in France might lie elsewhere entirely. Chinese workers seem likely to have carried the virus that caused the Great Flu pandemic of 1918-19, which may have killed more people around the world than the war itself.