No. 20 Squadron is the Royal Air Force's Operational Conversion Unit (OCU) for ground-based Tactical Air Command and Control, and Air Battle Management. It is part of the RAF's Air Surveillance and Control System (ASACS) and is based at RAF Boulmer. It was allocated the role on 1 June 2021. The squadron had previously been a flying squadron. In its last role, it was the Operational Conversion Unit for the UK's Joint Force Harrier; from September 1992 until March 2010 the squadron operated the BAE Harrier at RAF Wittering. History World War I The squadron was formed on 1 September 1915 at Netheravon, Wiltshire, as part of the Royal Flying Corps. In 1915, the German, and French and British air services had increasingly fought each other in the air for control of the skies to conduct reconnaissance. Combined with an expansion of the British Army, this prompted an expansion of the Royal Flying Corps in the second half of 1915, during which 20 Squadron was formed from a nucleus of Number 7 Reserve Aeroplane Squadron under the command of Captain C W Wilson MC. The squadron flew to France on 16 January 1916 landing first at St Omer and moving the following week to Clairmarais. It was equipped with the FE2B two-seat fighter-reconnaissance aircraft, which were replaced in June 1916 by the FE2D model, with an improved engine and armament. No. 20 Squadron was part of the Royal Flying Corps’ 2nd Brigade, working with the British 2nd Army, whose area of operations was around Ypres. The squadron's tasks included offensive patrols, photography, reconnaissance, and bombing by day and night. Of the squadron's 628 claimed combat victories, over 460 were confirmed by appearance in RFC Official Communiques. One of the combat victories that was most notable was that accredited to Second Lieutenant Woodbridge on 6 July 1917, who was the first British airman to wound Manfred von Richthofen when a 20 Squadron patrol was attacked by Richttofen's Jagdgeschwader 1. The skill and courage exhibited by members of 20 Squadron throughout the war was reflected in 71 gallantry awards. In addition to 34 Military Crosses, 19 Distinguished Flying Crosses, five Military Medals and other decorations, a Victoria Cross was posthumously awarded to Acting Flight Sergeant Thomas Mottershead, who died as a result of injuries sustained in combat on 7 January 1917. The squadron continued to operate from the St Omer area in