" Had we been called upon by the Staff to do so,” Hope wrote, referring to Oliver, “we could have furnished valuable information as to movements of submarines, minefields, minesweeping etc. But the Staff was obsessed with the idea of secrecy; they realized that they held a trump card and they worked on the principle that every effort must be made to keep our knowledge to ourselves, so as to be able to keep it up our sleeves for a really great occasion such as the German Fleet coming out in all their strength to throw down the gage in battle. In other words the Staff determined to make use of our information defensively and not offensively. "

― Erik Larson , Dead Wake: The Last Crossing of the Lusitania