Question: When did the military which introduced the tank to the battlefields of WWI start using the SA80?

full_context: Document 1: Ak 5: The first versions of the Ak 5 family were made by the Swedish company FFV Ordnance AB (now part of Saab Bofors Dynamics) under license from FN, with deliveries starting in 1986. This version of the Ak 5 is still in the inventory of the Swedish Armed Forces, but is no longer issued to soldiers, having been replaced by the Ak 5C and Ak 5D. This version uses fixed iron sights, and the Swedish Armed Forces have estimated that the maximum practical distance is 400 meters, but it can be used at longer ranges. This brings it in line with the M16, using the Swedish Armed Forces definition of maximum practical distance.
Document 2: Valentine tank: The Tank, Infantry, Mk III, Valentine was an infantry tank produced in the United Kingdom during the Second World War. More than 8,000 of the type were produced in eleven marks, plus various specialised variants, accounting for approximately a quarter of wartime British tank production. The many variants included riveted and welded construction, petrol and diesel engines and a progressive increase in armament. It was supplied in large numbers to the USSR and built under licence in Canada. Developed by Vickers, it proved to be both strong and reliable.
Document 3: Tanks in World War I: The development of tanks in World War I was a response to the stalemate that had developed on the Western Front. Although vehicles that incorporated the basic principles of the tank (armour, firepower, and all - terrain mobility) had been projected in the decade or so before the War, it was the alarmingly heavy casualties of the start of its trench warfare that stimulated development. Research took place in both Great Britain and France, with Germany only belatedly following the Allies' lead.
Document 4: Tanks in World War I: In Great Britain, an initial vehicle, nicknamed Little Willie, was constructed at William Foster & Co., during August and September 1915. The prototype of a new design that became the Mark I tank was demonstrated to the British Army on February 2 1916. Although initially termed ``Landships ''by the Landship Committee, production vehicles were named`` tanks'', to preserve secrecy. The term was chosen when it became known that the factory workers at William Foster referred to the first prototype as ``the tank ''because of its resemblance to a steel water tank.
Document 5: VT tank: The first VT tank, VT 1-1, was built in 1974 by Maschinenbau Kiel (MaK). One year later they produced the second VT tank, the VT 1-2. For further testing of the mobility and the concept of a tank with two main guns, five Gefechtsfeldversuchträger (GVT, "battlefield test-beds") were designed and built in 1975 and 1976.
Document 6: 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 7: ArmaLite AR-15: The ArmaLite AR - 15 was a select - fire, air - cooled, gas - operated, magazine - fed assault rifle manufactured in the United States between 1959 and 1964. Designed by American gun manufacturer ArmaLite in 1956, it was based on its AR - 10 rifle. The ArmaLite AR - 15 was designed to be a lightweight assault rifle and to fire a new high - velocity, lightweight, small - caliber cartridge to allow the infantrymen to carry more ammunition.
Document 8: ArmaLite AR-10: The final Artillerie Inrichtingen design is known as the "Portuguese" model AR-10. This final version incorporated all that had been learned to date about the AR-10, including infantry service rifle and field test reports. In addition to a heavier barrel with chrome-lined chamber, optional bipod, and the removable plastic/metal handguards of the Transitional model, the Portuguese variant had wider bolt lugs, a stronger extractor, a new simplified three-position gas regulator, and a cocking handle featuring a forward bolt assist. It is believed that approximately 4,000-5,000 Portuguese variants were produced; nearly all of them were sold to the Portuguese National Defense Ministry by the Brussels-based arms dealer SIDEM International in 1960. The AR-10 was officially adopted by the Portuguese paratrooper battalions ("Caçadores páraquedistas"), and the rifle saw considerable combat service in Portugal's counter-insurgency campaigns in Angola and Mozambique.
Document 9: 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 10: Covenanter tank: The Cruiser tank Mk V or A13 Mk III Covenanter was a British cruiser tank of the Second World War. The Covenanter was the first cruiser tank design to be given a name. Designed by the London, Midland and Scottish Railway as a better-armoured replacement for the Cruiser Mark IV, it was ordered into production in 1939 before pilot models were built. Problems with the design became apparent only after production was under way.
Document 11: Levavasseur project: The Levavasseur project was an early project for a tank designed in 1903 by the French Captain Léon René Levavasseur (1860-1942) of the 6th Artillery Battalion, described as a "self propelled cannon project" (French: "Projet de canon autopropulseur"). It is considered as the first description, made by a soldier, of what would come to be known as the tank. Levavasseur was a graduate of Ecole Polytechnique, of the promotion of 1881. According to "Armoured Fighting Vehicles of the World":
Document 12: Mark IV tank: The Mark IV was built by six manufacturers: Metropolitan (the majority builder), Fosters of Lincoln, Armstrong-Whitworth, Coventry Ordnance Works, William Beardmore and Company and Mirrlees, Watson & Co., with the main production being in 1917. The first order was placed for 1,000 tanks with Metropolitan in August 1916. It was then cancelled, reinstated and then modified between August and December 1916. The other manufacturers, contracted for no more than 100 tanks each, were largely immune to the conflict between Stern and the War Office.
Document 13: FN F2000: The FN F2000 is a 5.56×45mm NATO bullpup assault rifle, designed by FN Herstal in Belgium. The F2000 made its debut in March 2001 at the IDEX defence exhibition held in Abu Dhabi, in the United Arab Emirates. As of early 2019, the F2000 is removed from the FN international and US websites.
Document 14: SAR 21: The SAR 21 ("Singapore Assault Rifle - 21st Century") is a bullpup assault rifle designed and manufactured in Singapore. First revealed and subsequently adopted by the Singapore Armed Forces (SAF) in 1999, it was designed and developed over a four-year period and was intended to replace the locally license-built M16S1 by the Ministry of Defence (MINDEF), Singapore Army and the Chartered Industries of Singapore (CIS, now ST Kinetics). Many of its design features are directly intended to counter the weaknesses of the M16S1 as encountered operationally by some infantrymen.
Document 15: 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.
ground_truth: 1987
sub_queries: the tank was introduced by to the battlefields of world war i by Answer: the British Army
when did the British Army start using the sa80 Answer: 1987