was attached to No. 1 (Bomber) Group RAF, along with No. 300 (Polish) Squadron, and on 28 August was relocated to RAF Swinderby. The squadron flew its first combat mission on 14 September 1940. Three aircraft took part in a night bombing raid against German invasion barges intended for Operation Sea Lion, which had been collected at Boulogne. The date of the raid was later declared the date of the squadron's feast. The squadron suffered its first combat loss on 25 September 1940 when one of their Fairey Battles crashed over England (the loss was attributed to German night fighter, but a friendly fire incident was also suggested). In the following weeks the squadron bombed ports of Boulogne, Calais and Ostend without losses, performing a last mission on 15 October 1940. On 20 October 1940 the squadron was withdrawn from active service and re-equipped with heavier Vickers Wellington Mk IC bomber, with a crew of six instead of three. Crew training in night flying and use of the new aircraft proceeded through mid-December. Ground crew support for the squadron was expanded, however it did not reach British norms and amounted to some 220 men. On 22 December, the squadron's first mission in the Wellington (and the only that year) was flown against oil refinery facilities in Antwerp (three aircraft). In total, in 1940 44 missions were performed, with one Fairey Battle crew killed in action. Following a raid on Bremen on the night of 1 January 1941, the squadron was shaken when bad weather and poor visibility resulted in the loss of 3 of their aircraft and 11 airmen when the planes crashed while attempting to come down through a snowstorm at RAF Waddington. Wet ground made Swinderby airfield unsuitable for use, and the entire squadron was grounded (from February it operated temporarily from other airfields). After several weeks the weather improved and 301 Squadron rejoined the bombing campaign over France and Germany. Targets struck included, among others, Bremen, Hamburg, Cologne, Brest and Essen. On 17 April 1941 three crews took part in bombing of Berlin for the first time. On 18 July 1941 the two Polish bomber squadrons were moved to RAF Hemswell. In 1941 the squadron's aircraft undertook 436 missions, with a loss of 9 crews. On 12 February 1942 the squadron took part in an exceptional daylight operation against Channel Dash of German battleships, but did not