This campaign had a very direct bearing upon our North Sea strategy, for at the date at which the Battle of Jutland was fought, about two and a half million tons of British, Allied, and neutral shipping had been sunk by submarine and mine. Had the war imposed no other attacks upon merchant shipping, the percentage lost would not have been very formidable. In the eighteen months that had elapsed since the first organized submarine attack on trade, it represented a rate of sinking of less than a million and three-quarter tons a year, a loss which the Allies and neutrals could easily have counteracted by more energetic building. But more than half of Great Britain’s ocean-going shipping had been commandeered for various war purposes and already in 1916 it had become obvious that the remaining stock of ships could not seriously be diminished without grave embarrassment, either to civil supply, to our financial position, to our military power abroad, or to all three. What was much more serious was this: It was a well-known fact that immediately after the German Government decided to blockade by submarine, a very large building programme was put in hand. The programme, as we have seen, had begun to materialize at the beginning of 1916, and it was Germany’s resources in new ships that was Tirpitz’s justification for risking a quarrel with America, so certain did the ruin of England seem, were ruthlessness of method combined with the employment of larger and larger numbers. The Higher Naval Command, then, in this country were fully aware of the extreme importance of being able to deal drastically with this menace, should it once more arise to threaten our sea communications. They also knew that it was certain to arise. And, again, they knew that the under-water threat could only be completely met by an under-water antidote. In the nature of things, as we have seen, there could be no complete reply to the submarine except by mines laid in continuous barrage outside the German harbours, and this in turn was a thing that could not be done unless the German Fleet were destroyed. Whatever reason there may have been in 1914 and 1915 for holding the Churchill doctrine that a victory was unnecessary, the brief submarine campaign of 1916 must have undeceived the blindest. For this campaign had not only shown that ruthlessness could double the rate of sinking, it had also shown that our stock counter-measures were ineffective to thwart it. It was, then, a matter of the very highest military importance to the cause of the Alliance that the German Fleet should be disposed of, so that the renewal of the German submarine campaign should be virtually impossible.