 Complete the following phrase:  In April 1937, the squadron was re-formed as No. 37 Bomber Squadron at RAF Feltwell in Norfolk, East Anglia from a nucleus provided by No. 214 Squadron RAF, equipped with the Handley Page Harrow heavy bomber. It re-equipped with Vickers Wellingtons in May 1939, retaining them at the outbreak of 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 