It was during the Battle of Britain, in which Axis aircraft flew over the English Channel to directly challenge the British mainland itself, that the BR.20 showed its limitations for the first time. On 10 September 1940, the "Corpo Aereo Italiano" was formed, with 13° and 43° "Stormi" equipped with 80 brand-new BR.20Ms, to fight in the Battle of Britain. During the ferry operation from Italy to their bases in Belgium, five aircraft crash-landed because of technical failures and a lack of navigational training, while a further 17 BR.20s were forced to land en route due to poor visibility. On the night of 24 October, the 13° and 43° took off for their first bombing mission, over Harwich, deploying eight BR.20s each. One bomber crashed on takeoff, as a result of engine failure, while two more got lost on their return, failing to find their airfield and their crews bailing out. On 29 October, 15 aircraft of 43° "Stormo" bombed Ramsgate, in daylight, with no loss.