These considerations were not lost upon the Germans. They greatly increased the fortifications of Heligoland, and they proceeded to fortify one after another such of the Frisian Islands as were in any way suitable for our purposes. At the same time a new and potent factor appeared upon the scene—the submarine. The submarine not only rendered the capture and maintenance of an oversea base or bases far more difficult and, as some authorities have steadfastly held, impossible, but it threatened with destruction our cruisers and battleships without whose constant support our flotillas would easily have been destroyed by the enemy’s cruisers. This was the situation in October, 1911, when immediately after the Agadir crisis I became First Lord and proceeded to form a new Board of Admiralty. Seeing that we had not for the time being the numerical force of destroyers able to master the destroyers of the potential enemy in his home waters, nor the power to support our flotillas with heavy ships, and having regard also to the difficulty and hazard in all the circumstances of storming and capturing one of his now fortified islands, we proceeded forthwith to revise altogether the War Plans and substitute, with the full concurrence of our principal commanders afloat, the policy of distant blockade set up in the Admiralty War Orders of 1912. The policy of distant blockade was not adopted from choice, but from necessity. It implied no repudiation on the part of the Admiralty of their fundamental principle of aggressive naval strategy, but only a temporary abandonment of it in the face of unsolved practical difficulties; and it was intended that every effort should be made, both before and after a declaration of war, to overcome those difficulties. It was rightly foreseen that by closing the exits from the North Sea into the Atlantic Ocean, German commerce would be almost completely cut off from the world. It was expected that the economic and financial pressure resulting from such a blockade would fatally injure the German power to carry on a war. It was hoped that this pressure would compel the German fleet to come out and fight, not in his own defended waters, but at a great numerical disadvantage in the open sea. It was believed that we could continue meanwhile to enjoy the full command of the seas without danger to our sea communications or to the movement of our armies, and that the British Isles could be kept safe from invasion. There was at that time no reason to suppose that these conditions would not continue indefinitely with undiminished advantage to ourselves and increasing pressure upon the enemy. So far as all surface vessels are concerned, and certainly for the first three years of the war, these expectations were confirmed by experience.