British monitoring stations detected X Verfahren radio beams being laid across northern England, United Kingdom, and suspected a German attack would take place on the city of Sheffield. In the evening, 13 He 111 bombers of Kampfgruppe 100 arrived over the Sheffield suburbs of Norton Lees and Gleadless at 1941 hours, dropping 16 SC50 high explosive bombs, 1,009 B1 E1 ZA incendiaries, and 10,080 B1 E1 incendiaries. Shortly after, three groups of German bombers, the main force, attacked. The first group was consisted of 36 Ju 88 bombers and 29 He 111 bombers; the second group was consisted of 23 Ju 88 bombers, 74 He 111 bombers, and 7 Do 17 bombers; the third group was consisted of 63 Ju 88 bombers and 35 He 111 bombers. The 280 German aircraft heavily damaged the city center and residential districts through the night through 0400 hours on the next day.
