In the Declaration of Paris, renewed and extended by the Declaration of London, the maritime States have agreed that in any future war enemy goods in a neutral ship are to be safe from capture unless the ship is running a blockade, which must be effective.  Whether Great Britain was well or ill advised in accepting this rule is a question which it is now useless to discuss, for the decision cannot be recalled, and the rule must be regarded as established beyond controversy.  Its effect is greatly to diminish the pressure which a victorious navy can bring to bear upon a hostile State.  It deprives Great Britain of one of the most potent weapons which she employed in the last great war.  To-day it would be impracticable even for a victorious navy to cut off a continental State from seaborne traffic.  The ports of that State might be blockaded and its merchant ships would be liable to capture, but the victorious navy could not interfere with the traffic carried by neutral ships to neutral ports.  Accordingly, Great Britain could not now, even in the event of naval victory being hers, exercise upon an enemy the pressure which she formerly exercised through the medium of the neutral States.  Any continental State, even if its coasts were effectively blockaded, could still, with increased difficulty, obtain supplies both of raw material and of food by the land routes through the territory of its neutral neighbours.  But Great Britain herself, as an insular State, would not, in case of naval defeat, have this advantage.  A decisive defeat of the British navy might be followed by an attempt on the part of the enemy to blockade the coasts of Great Britain, though that would no doubt be difficult, for a very large force would be required to maintain an effective blockade of the whole coast-line.

It is conceivable that an enemy might attempt in spite of the Declaration of London to treat as contraband food destined for the civil population and this course ought to be anticipated, but in the military weakness of Great Britain an enemy whose navy had gained the upper hand would almost certainly prefer to undertake the speedier process of bringing the war to an end by landing an army in Great Britain.  A landing on a coast so extensive as that of this island can with difficulty be prevented by forces on land, because troops cannot be moved as quickly as ships.

The war in the Far East has shown how strong such an army might be, and how great a military effort would be needed to crush it.  The proper way to render an island secure, is by a navy strong enough to obtain in war the control of the surrounding sea, and a navy unable to perform that function cannot be regarded as a guarantee of security.