Towards the end of 1915, or early in 1916, the disadvantages attendant on basing the Fleet so far north as Scapa Flow, were discussed between Sir Henry Jackson (then First Sea Lord) and myself. We both felt that, with the Fleet at the northern base, the difficulties of intercepting the High Sea Fleet during coast raids, and of dealing with landing raids covered by the High Sea Fleet, were so considerable as to make it eminently desirable to base the whole Fleet farther south, if this were feasible. A discussion took place at Rosyth, and as the result I suggested a scheme of submarine obstructions across the Firth of Forth, which would admit not only of berthing the whole Grand Fleet in that anchorage, but would also allow of gunnery and torpedo practices being carried out with a considerable degree of safety in the Forth, so that the Fleet, if based there, could keep up its fighting efficiency. Many senior officers in the Grand Fleet were not in favour of the idea, for two reasons: first, that the Fleet could be mined in by the enemy with much greater ease when in the Forth than when at Scapa; and, secondly, that practices could not be so efficiently carried out in the Forth. There was much weight in both these objections, although the difficulties of carrying out practices in the Forth were exaggerated; but the strategic advantage, in my opinion, outweighed them, and the scheme was proceeded with as proposed. That part of the scheme which admitted of the safe carrying out of practices was completed by December, 1916, and the whole of the new obstructions were in place by July, 1917, nearly a year later, it is true, than the anticipated date. The result certainly justified the conclusion arrived at. When the conditions made it at all probable that the High Sea Fleet might put to sea for an operation in southern waters, the Grand Fleet assembled in the Firth of Forth, and the undoubted disadvantages of the southern base were neutralised by skilful dispositions on the part of the flag officers responsible. The protection of the Grand Fleet bases against submarine attack was only one of the many factors necessary for their development. In pre-War days, although it had been decided that the use of northern bases would be necessary in the event of a war with Germany, the bases had not been prepared to meet the new situation. It is, perhaps, desirable to remove any misunderstanding as to the causes of this failure. (_a_) The decision had not long been taken, and (_b_) The necessary financial provision was lacking. Under the first of these headings the base at Scapa Flow was affected, and, under the second, that at Rosyth, where for some time progress in the development of the base had been arrested.