 The aerial operations against shipping in the English Channel began, what the German airmen called, the Kanalkampf phase of the Battle of Britain.Sperrle and Kesselring miscalculated, or were misled by intelligence, into underestimating the number of fighter aircraft available to Fighter Command—they put the RAF total at 450 aircraft when the real figure was 750.Chronic intelligence failures on British production, defence systems and aircraft performance inhibited the German air operation throughout the battle.