Mk IV Mk IV light bombers, joining 2 Group on 3 December and based at RAF Wyton. The squadron was non-operational for many weeks after receiving Blenheims, and in February 1940, several of its Blenheims were withdrawn and transferred to Finland during the Winter War. On 14 April 1940 one of the squadron's Blenheims was taken on an unauthorized flight by AC2 JFB Lewis and crashed in the Thames Estuary. His body was not found and he is remembered on the Runnymede Memorial. On 10 May 1940, Germany invaded France and the Low Countries, with two of the squadron's Blenheims (on of which was lost) flying a reconnaissance mission over the Hague in the morning, which resulted in a series attacks by squadrons of 2 Group against airfields in the Netherlands being used to land German paratroops, with 40 Squadron attacking Ypenburg Airport in the squadron's first bombing attack of the war. The squadron continued to launch raids against the advancing German forces, which sometimes involved flying from airfields in France. Late in the month, 40 Squadron, along with the rest of 2 Group, was employed in attacks against German forces advancing on the troops of the British Expeditionary Force trapped at Dunkirk. Operations included attacks on enemy motor transport, bridges and attempting to block roads by bombing houses by the sides of the roads. After the fall of France, attacks switched to barges waiting at Channel ports for the planned German invasion of Britain. 'B' Flight of the squadron moved to RAF Alconbury on 8 October 1940. On 1 November 1940, the squadron, along with 15 Squadron, transferred to 3 Group, replacing 37 and 38 Squadrons, which were transferred to the Middle East. As a result, it converted to Vickers Wellingtons to fit with its new role of night bombing against German industrial targets. The squadron carried out its first operations using the Wellington on the night of 21/22 December 1940, when three aircraft attacked Antwerp docks. On 1 February 1941, the remainder of the squadron joined up with 'B' Flight at Alconbury. In October 1941, most of the squadron was detached to operate from Malta, with a skeleton remaining at Alconbury. The Malta-based detachment was employed in attacks on Italian airfields, and ports in Sicily and Tripolitania to disrupt supplies to North Africa, as well as nuisance raids by single aircraft, spending hours over the target, forcing the