Sgt. Bełc, while Sgt. Karubin claimed a Bf 109. On 5 October 1940, Polish pilots claimed five Bf 110s and four Bf 109s, though P/O Wojciech Januszewicz was killed. (Erprobungsgruppe 210 lost two Bf 110s Jabos and JG 3 and JG 53, a Bf 109 each). A fight over the Thames Estuary on 7 October saw claims for three Bf 109s of LG 2. On 8 October, Czech ace Josef František died in an air crash. He was the highest scoring pilot of 303rd Squadron and the second highest scoring ace in the Battle of Britain, with 17 claims. On 11 October 1940, the squadron was transferred for a rest to Leconfield in No. 12 Group, ending its participation in the Battle of Britain. No. 303 Squadron claimed the largest number of aircraft shot down of the 66 Allied fighter squadrons engaged in the Battle of Britain, even though it joined the fray two months after the battle had begun. Its success in combat can be mainly attributed to the years of extensive and rigorous pre-war training many of the long-serving Polish veterans had received in their homeland, far more than many of their younger and inexperienced RAF comrades then being thrown into the fray. Tactics and skill also played a role; on one occasion, No. 303's Sgt Stanislaw Karubin resorted to extreme tactics to bring down a German fighter. Following a prolonged air battle, Karubin was chasing a German fighter at treetop level. As he closed in on the tail of the German fighter, Karubin realised that his Hurricane had run out of ammunition. Rather than turning back to base, he closed the distance and climbed right above the German fighter. The German pilot was so shocked to see the underside of the Hurricane within arm's reach of his cockpit that he instinctively reduced his altitude to avoid a collision and crashed into the ground. At the time it was withdrawn from battle for a rest on 11 October 1940, the squadron had claimed 126 kills in six weeks. Relative to enemy aircraft downed, Polish losses were small with 18 Hurricanes lost, seven pilots killed and five badly wounded. 303 Squadron was one of the top fighter units in the battle and the best Hurricane-equipped one. It also had the highest kill-to-loss ratio, 2.8:1. However, J. Alcorn was not able to attribute 30 aircraft shot down to any particular