Glance for a moment at a map of Europe――it will be seen that Great Britain lies like a huge breakwater across the sea approaches to Northern Europe, with Ireland as a smaller breakwater across the approaches to Great Britain. We realize that in the Great War, Germany was in the most unfavourable position possible for blockading England’s sea communications, her submarines having first to get outside this breakwater through a narrow outlet sown with mines and closely watched, and on completion of this mission make the same hazardous return to their bases. No stronger proof of the potential menace of the submarine in future war can be found than that Germany, with so few submarines and despite such an immense handicap, sank 8,500,000 tons of shipping, and all but stopped the beat of Britain’s heart. Contrast with this the geographical position of France, the chief submarine power of the immediate future. Her Atlantic bases lie directly opposite the sea approaches to the British Isles――in an ideal position for submarine action to block the sea arteries on which England’s life depends. Of potential significance also is the position of Ireland, an outer breakwater lying across the gateways to Great Britain, for should Ireland ever lend its harbours to an enemy as submarine bases, the odds would be hopeless. Turn again to the Mediterranean, another long and narrow sea channel through which runs our artery with the East, and where our main naval force is now concentrated. Note that our ships, naval or mercantile, must traverse the _length_ of this channel, and worse still, have to filter through a tiny hole at each end――the straits of Gibraltar and the Suez Canal――while midway there is a narrow “waist” between Sicily and Tunis, barely ninety miles across. Then look at the geographical position of Toulon and of the French naval ports on the North African coast, and note how the _radii_ of submarine attack intersect the long single line of British sea communication. Is it not obvious that if in a future war any Mediterranean power was numbered among Britain’s enemies, her fleet would find it difficult enough to protect itself against submarines, let alone protect merchant convoys and troop transports? When to the proved menace of submarine power is added the potential effect of aircraft attack against shipping in the narrow seas, it is time the British people awoke to the fact that, in case of such a war, the Mediterranean would be impassable, and that this important artery would have to be abandoned. Thus, as a strategical asset, the Suez Canal has lost a large part of its value in face of modern naval and air development――for in such a war we should be driven to close the Mediterranean route, and divert our imperial communications round the Cape of Good Hope.