World War II, when it formed part of 3 Group. The squadron flew its first operational mission of the war on 3 September 1939, an unsuccessful armed reconnaissance mission by six Wellingtons to the Schillig Roads to search for German warships. On 18 December 1939, 37 Squadron contributed six aircraft to a sortie by 24 Wellingtons against shipping in the Heligoland Bight. The formation came under heavy attack by German fighters, with five out of 37 Squadron's six Wellingtons shot down, with 21 men killed. In total, twelve Wellingtons were shot down. In November 1940, the squadron moved to the Middle East, with the squadron's aircraft being flown via Malta, from where they flew a few missions before arriving in Egypt on 14 November, with one of its crews claiming an Italian seaplane shot down on the ferry flight from Malta to Egypt. The squadrons ground crew were sent to Egypt by ship, being ferried from Gibraltar to Alexandria aboard the cruiser , which took part in the Battle of Cape Spartivento on 27 November and came under air attack the next day before reaching Egypt and disembarking the squadron's personnel. The Wellingtons of 37 Squadron, together with the other two Egypt-based Wellington squadrons, 38 and 70 Squadrons, were deployed in support of Operation Compass, the British offensive against Italian forces in the Western Desert from 8/9 December, operating against airfields used by the Italians. In February 1941 the squadron was transferred to Greece to support Greek resistance to the Italian invasion. It was used to attack targets in Albania and Italy, and also for supply dropping to Greek troops. Following the German invasion of Greece in April 1941, the squadron's Wellingtons were used to carry out attacks on Bulgaria, but by 17 April the German advance forced the squadron to be evacuated back to Egypt. On 1 May 1941, a detachment of eight Wellingtons from 37 Squadron were deployed to RAF Aqir in Palestine as a response to Iraqi threats to the British airbase at Habbaniya, and the next day took part in bombing raids against Iraqi positions outside Habbaniya in the opening moves of the Anglo-Iraqi War. The detachment moved to Shaibah in Iraq later that day, and continued to raid Iraqi positions and airfields for the next few days. The remainder of the squadron, meanwhile, continued to fly raids against German and Italian airfields in southern Greece