 The first raids came as a surprise and were met by ineffective responses . On the first raid a Beaufighter from 604 Squadron shot down a single bomber , while the next three raids resulted in no kills , and the next a single kill again . But as the pattern of the attacks grew more obvious — short attacks against smaller coastal cities — the defense responded . Four bombers were shot down on the night of 3 / 4 May , two more on 7 / 8th , one on 18th , two on the 23rd . The Luftwaffe changed their tactics as well ; their bombers would approach at low altitude , climb to spot the target , and then dive again after releasing their bombs . This meant that interceptions with the Mk . IV were possible only during the bomb run . 
