Page 48: September 21st 1940 421 Flight. One of the problems that Fighter Command encountered was the fact that when radar picked up approaching enemy aircraft and formations, it was not known as to what type of aircraft they were until clarified by spotters or the Observer Corps. With the approach of German bombers, Keith Park had just enough time to scramble his fighters, get to the correct height to attack and intercept the enemy as it crossed the coast. But with this new tactic of sending formations of Bf109s, often in Geschwader force, there was not enough time to scramble the fighters and meet them as they crossed the coast. As experienced over the last few days and on those occasions that Bf109 formations made their intended attacks on British targets, they generally would be well over the coastline and much closer to London before they were intercepted by British fighters. It was on this day that Air Chief Marshal Hugh Dowding was to authorise the formation of a new unit that was to become known as 421 Flight. This was instigated in collaboration with Keith park because it was now felt that with Bf109 formations that could cross the Channel quicker than the bombers that they once escorted, their would be no chance of British fighters intercepting them in time once they had been positively identified. The task of 421 Flight that was equipped with Hurricanes, was to fly in small formations on reconnaissance missions over the Channel to report on any build up and composition of these formations prior to them reaching the English coastline. This way, as well as the detection being made on radar stations along the coast of their location, 421 Flight would be vectored into a position where they could provide details back to their sector station of type and strength of the enemy much earlier than if it was left to the Observer Corps alone. Initially, the flight was formed at Gravesend in mid October and on October 31st was posted to West Malling and before the end of 1940 they had been moved to Hawkinge. The formation of 421 Flight (which was later to become 91 Squadron) was naturally too late for the Battle of Britain. Some authorities say that such a squadron should have been formed earlier so as to provide early indications of strength and composition of the enemy. But again, this would have been another of the many debatable points that arose during the Battle of Britain.
