 In the Operations notes, Formation Flying, orders specifically stated that the formation, as a whole, was not to stay together, saying each six aircraft section was to be a self-contained defensive unit, flying at different heights, stating that more than 12 aircraft per formation made it unwieldy and unmanageable by one leader. Even so, the notes also pointed to the importance of holding a formation within one's own section. If a section leader endeavoured to follow the formation leader (Wing Commander Kellet) to the detriment of their section, the formation would break apart. Bomber formations were built on the idea of mutual protection; if the formation came apart, each bomber would have to fend for itself, which would enable an enemy to pick off the bombers one by one. Squadron Leaders Guthrie and Hue-Williams did not heed this advice during the battle. Wing Commander Kellett had followed the notes, and he lost only one aircraft. Harris had also kept his formation together, and lost none of his Wellingtons. Within a few weeks, a debate began on shifting air attacks to the cover of darkness, with Hewitt favouring this alternative.
