In the Egyptian case there was no distinction between the two objectives at all.  Napoleon’s expedition sailed in one mass.  Yet in the handling of his fleet Nelson preserved the essential idea.  He organised it into three “sub-squadrons,” one of six sail and two of four each.  “Two of these sub-squadrons,” says Berry, his flag-captain, “were to attack the ships of war, while the third was to pursue the transports and to sink and destroy as many as it could”; that is, he intended, in order to make sure of Napoleon’s army, to use no more than ten, and possibly only eight, of his own battleships against the eleven of the enemy.

Many other examples could be given of British insistence on making the enemy’s army the primary objective and not his fleet in cases of invasion.  No point in the old tradition was more firmly established.  Its value was of course more strongly marked where the army and the fleet of the enemy endeavoured to act on separate lines of operation; that is, where the army took the real offensive line and the fleet the covering or preventive line, and where consequently for our own fleet there was no confusion between the two objectives.  This was the normal case, and the reason it was so is simple enough.  It may be stated at once, since it serves to enunciate the general principle upon which our traditional system of defence was based.

An invasion of Great Britain must always be an attempt over an uncommanded sea.  It may be that our fleet predominates or it may be that it does not, but the command must always be in dispute.  If we have gained complete command, no invasion can take place, nor will it be attempted.  If we have lost it completely no invasion will be necessary, since, quite apart from the threat of invasion, we must make peace on the best terms we can get.  Now, if the sea be uncommanded, there are obviously two ways in which an invasion may be attempted.  Firstly, the enemy may endeavour to force it through our naval defence with transports and fleet in one mass.  This was the primitive idea on which the Spanish invasion of Philip the Second was originally planned by his famous admiral, Santa-Cruz.  Ripening military science, however, was able to convince him of its weakness.  A mass of transports and warships is the most cumbrous and vulnerable engine of war ever known.  The weaker the naval defence of the threatened country, the more devoutly will it pray the invader may use this device.  Where contact with the enemy’s fleet is certain, and particularly in narrow seas, as it was in this case, such a course will give the defender all the chances he could desire, and success for the invader is inconceivable, provided always we resolutely determine to make the army in its transports our main objective, and are not to be induced to break our head against its escort.