Khaki drill or KD was the term for a type of fabric and the British military uniforms made from them. Khaki Drill was worn as a combat uniform from 1900 to 1949 and was most often used in desert and tropical service. A variant, still referred to a Khaki Drill or KD's, is worn by the UK Armed Forces in noncombatant warm weather countries where the British are actively serving (e.g. personnel stationed at R.A.F. Akrotiri in Cyprus will wear any of four working variants of this uniform). Generally KD was a series of different uniform patterns of light khaki cloth, generally cotton, first worn by British and British Empire soldiers in the Boer War. Canada developed its own pattern after the First World War, and the uniform was commonly worn in Canada, with officers again having the option of finer garments privately purchased. In the Second World War, Canadians serving in Jamaica and Hong Kong wore Canadian pattern KD; the I Canadian Corps troops in Italy wore KD supplied in theatre by the British, generally of British, Indian or US (War Aid) manufacture.

World War I (WWI), which was predominantly called the World War or the Great War from its occurrence until 1939 (World War II), and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918. It involved all the world's great powers, which were assembled in two opposing alliances: the Allies (based on the Triple Entente of the United Kingdom, France and Russia) and the Central Powers (originally centred around the Triple Alliance of Germany, Austria-Hungary and Italy; but, as Austria–Hungary had taken the offensive against the agreement, Italy did not enter into the war). These alliances both reorganised (Italy fought for the Allies), and expanded as more nations entered the war. Ultimately more than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history. More than 9 million combatants were killed, largely because of enormous increases in lethality of weapons, thanks to new technology, without corresponding improvements in protection or mobility. It was the sixth-deadliest conflict in world history, subsequently paving the way for various political changes such as revolutions in the nations involved.