Traffic analysis indicated that Scharnhorst and Gneisenau were preparing to sail. Human intelligence told the Admiralty that the ships were not ready, and that assessment received greater weight. Their subsequent sortie during the Norwegian operations included the sinking of HMS Glorious. In this interpretation, the missed warning resulted from how conflicting sources were weighed. A technical indication of activity lost out to an existing assessment of the ships' readiness.
Notable Point · 1:40:26-1:41:39
Conflicting warnings before Scharnhorst and Gneisenau sailed
The Scharnhorst and Gneisenau example examines why a traffic-analysis warning was discounted in favor of human intelligence.