support of the British Army around Ypres for most of the war, at airfields such as Boisdinghem and Saint Marie Cappel. On 21 September 1917, it completed its re-equipment with the replacement for the FE2D, the Bristol Fighter, which was to equip the squadron for the next 15 years. The squadron conducted daily detached operations from Bruay, near Bethune during the major German offensive in March 1918, and moved further south to several airfields east of Amiens as allied armies moved forward during the 100 Days Offensive. The squadron transferred from the Royal Flying Corps to the newly formed Royal Air Force in April 1918. After the Armistice, 20 Squadron moved to Ossogne, east of Namur in Belgium, where it stayed until May 1919. The Northwest Frontier After the Afghan Army invaded the Northwest Frontier province of India in early May 1919, 20 Squadron was ordered to sail for India as reinforcement for the two squadrons already in place. They were to conduct similar air operations to those that they had undertaken on the Western Front in support of the Army. The squadron arrived at RAF Risalpur on 19 June 1919 and was the first squadron to fly the Bristol Fighter in India. Although the Afghan invasion had been defeated, 20 Squadron was retained on the Northwest Frontier in the new role of Air Control. For most of the next 20 years, the Squadron was mainly based at RAF Peshawar, with regular moves forward to locations such as Miranshah and Shabkadar. The squadron developed new techniques of Air Control. Their Bristol fighters conducted reconnaissance, both independently and for the Army in the field. The squadron also undertook more peaceful and humanitarian roles. Two Wapitis, on trial in India and flown by 20 Squadron crews, escorted the RAF Victoria and DH9s conducting the Kabul airlift of 1929. They were the only aircraft on the North-West Frontier equipped with Wireless Telephony sets, which were used to maintain contact with Peshawar during the operation. It responded to the large earthquake which hit Quetta on 31 May 1935; the squadron deployed 9 aircraft to ferry medical personnel and supplies to and around the area. It also flew vaccine to Kabul on 19 August 1936. In August 1928, the famous archaeologist, diplomat, army officer and writer T E Lawrence was posted to 20 Squadron, having joined the RAF as a non-commissioned airman. He served as