Question: When did the operator of Blowpipe start wearing khaki?

full_context: Document 1: Swingfire: Swingfire was developed by Fairey Engineering Ltd and the British Aircraft Corporation, together with Wallop Industries Ltd and minor subcontractors. It replaced the Vickers Vigilant missile in British service. Its design incorporated elements from its predecessor the Vigilant and the experimental Orange William missile.
Document 2: Airman Battle Uniform: On 2 October 2007, the Air Force began issuing the ABU to enlisted trainees in Basic Military Training at Lackland AFB and was issued to the Class of 2012 at the United States Air Force Academy on 26 June 2008, and is now available for purchase by all Airmen. Since 2008, it has been issued to Airmen deploying to locations in CENTCOM, including Kuwait, Iraq and Afghanistan. Personnel in other countries were issued DCU uniforms while inventory lasted. The ABU is available at Army and Air Force Exchange Service (AAFES) military clothing stores. Although the Air Force has officially recognized color variations in different set of ABUs, all variations are currently authorized to wear and the problem should be fixed when the patterns are finalized within a year.
Document 3: SA80: The SA80 is a British family of 5.56 × 45mm NATO small arms, all of which are selective fire, gas - operated assault rifle s. The L85 rifle variant of the SA80 family has been the standard issue service rifle of the British Armed Forces since 1987, replacing the L1A1 variant of the FN FAL. The first prototypes were created in 1976, with production ending in 1994. The A1 variant was significantly upgraded in the early 2000s by Heckler & Koch as the SA80A2 and remains in service as of 2017. In mid-2016 a prototype A3 variant was showcased which further improved on the weapon and is reportedly being considered to extend the out of service date beyond 2025.
Document 4: Red coat (military uniform): Red coat or Redcoat is a historical item of military clothing used widely, though not exclusively worn, by most regiments of the British Army from the 17th to the 20th centuries. From the mid-17th century to the 19th century, the uniform of most British soldiers (apart from artillery, rifles and light cavalry) included a madder red coat or coatee. From 1873 onwards, the more vivid shade of scarlet was adopted for all ranks, having previously been worn only by officers, sergeants and all ranks of some cavalry regiments.
Document 5: British Army during the Second World War: The pre-war British Army was trained and equipped to be a small, mechanised, professional army. Its main function was to garrison the British Empire. It became evident early in the war that its initial structure and manpower was woefully unprepared and ill - equipped for a war with multiple enemies on multiple fronts. The British Army, an all - volunteer force until 1939, was small in comparison to its enemies at the start of the Second World War in 1939, as it had been in the First World War. By the end of the Second World War, however, over 3.5 million men had served in the British Army.
Document 6: Navy blue: Navy blue got its name from the dark blue (contrasted with white) worn by officers in the British Royal Navy since 1748 and subsequently adopted by other navies around the world. When this color name, taken from the usual color of the uniforms of sailors, originally came into use in the early 19th century, it was initially called "marine blue", but the name of the color soon changed to "navy blue".
Document 7: Anti-aircraft warfare: In the 1982 Falklands War, the Argentine armed forces deployed the newest west European weapons including the Oerlikon GDF-002 35 mm twin cannon and SAM Roland. The Rapier missile system was the primary GBAD system, used by both British artillery and RAF regiment, a few brand-new FIM-92 Stinger were used by British special forces. Both sides also used the Blowpipe missile. British naval missiles used included Sea Dart and the older Sea Slug longer range systems, Sea Cat and the new Sea Wolf short range systems. Machine guns in AA mountings was used both ashore and afloat.
Document 8: Uniforms of the United States Navy: The Navy first authorized a khaki uniform in 1913 as a practical garment for early naval aviators; they were given permission to wear Marine Corps khaki uniforms with naval insignia, when flying or working on aircraft. Khakis were authorized aboard submarines in 1931 and as a working uniform on all ships ten years later.
Document 9: SA80: After receiving feedback from users and incorporating the various design changes requested, including adapting the rifle for use with the heavier Belgian SS109 version of the 5.56×45mm round and improving reliability, the weapon system was accepted into service with the British Armed Forces in 1985 as the SA80. The SA80 family originally consisted of the L85A1 Rifle, the L86A1 Light Support Weapon (LSW), and L98A1 Cadet GP Rifle. The first weapons were issued in October 1985.
Document 10: United States Air Force: The first USAF dress uniform, in 1947, was dubbed and patented "Uxbridge Blue" after "Uxbridge 1683 Blue", developed at the former Bachman-Uxbridge Worsted Company. The current Service Dress Uniform, which was adopted in 1993 and standardized in 1995, consists of a three-button, pocketless coat, similar to that of a men's "sport jacket" (with silver "U.S." pins on the lapels, with a silver ring surrounding on those of enlisted members), matching trousers, and either a service cap or flight cap, all in Shade 1620, "Air Force Blue" (a darker purplish-blue). This is worn with a light blue shirt (Shade 1550) and Shade 1620 herringbone patterned necktie. Enlisted members wear sleeve insignia on both the jacket and shirt, while officers wear metal rank insignia pinned onto the coat, and Air Force Blue slide-on epaulet loops on the shirt. USAF personnel assigned to Base Honor Guard duties wear, for certain occasions, a modified version of the standard service dress uniform, but with silver trim on the sleeves and trousers, with the addition of a ceremonial belt (if necessary), wheel cap with silver trim and Hap Arnold Device, and a silver aiguillette placed on the left shoulder seam and all devices and accoutrement.
Document 11: Lightweight Multirole Missile: The Lightweight Multirole Missile (LMM; previously known as FASGW(L)) is a lightweight air-to-surface and surface-to-surface missile under development by Thales Air Defence for the United Kingdom. The Ministry of Defence (MOD) has placed an initial order for 1,000 missiles and deliveries were due to start in 2013. The missile is known as Martlet in British service.
Document 12: Eton College: The long-standing claim that the present uniform was first worn as mourning for the death of George III is unfounded. "Eton dress" has undergone significant changes since its standardisation in the 19th century. Originally (along with a top-hat and walking-cane), Etonian dress was reserved for formal occasions, but boys wear it today for classes, which are referred to as "divisions", or "divs". As stated above, King's Scholars wear a black gown over the top of their tailcoats, and occasionally a surplice in Chapel. Members of the teaching staff (known as Beaks) are required to wear a form of school dress when teaching.
Document 13: Blowpipe (missile): The Shorts Blowpipe is a man-portable surface-to-air missile that was in use with the British Army and Royal Marines from 1975. It was superseded by an interim design, Javelin, and later the greatly improved Starstreak.
Document 14: PIAT: The Projector, Infantry, Anti Tank (PIAT) Mk I was a British man-portable anti-tank weapon developed during the Second World War. The PIAT was designed in 1942 in response to the British Army's need for a more effective infantry anti-tank weapon and entered service in 1943.
Document 15: Service Dress (British Army): Service Dress was the new style of khaki service dress uniform introduced by the British Army for use in the field from the early 1900s, following the experiences of a number of imperial wars and conflicts, including the Second Boer War. This variant of uniform continues to be worn today, although only in a formal role, as No. 2 Pattern dress.
ground_truth: early 1900s
sub_queries: Blowpipe >> operator Answer: British Army
when did British Army start wearing khaki Answer: early 1900s