At the end of June 1940, following the fall of France, 31 of Fighter Command's 61 fighter squadrons were equipped with Hurricanes. The Battle of Britain officially lasted from 10 July until 31 October 1940, but the heaviest fighting took place between 8 August and 21 September. Both the Supermarine Spitfire and the Hurricane are renowned for their part in defending Britain against the Luftwaffe; generally, the Spitfire would intercept the German fighters, leaving Hurricanes to concentrate on the bombers, but, despite the undoubted abilities of the "thoroughbred" Spitfire, it was the "workhorse" Hurricane that scored the higher number of RAF victories during this period, accounting for 55 per cent of the 2,739 German losses, according to Fighter Command, compared with 42 per cent by Spitfires. On 8 August 1940, Hurricanes of No. 145 Squadron were recorded as having fired the first shots of the Battle of Britain. The highest scoring Hurricane squadron during the Battle of Britain was the No. 303 Polish Fighter Squadron. This squadron also had the distinction of having the highest ratio of enemy aircraft destroyed to own losses suffered.