ation; 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.

Where, however, contact is not certain, the invasion over an uncommanded
sea may succeed by evasion of the defender's battle-fleet, as it did in the
case of Napoleon's invasion of Egypt. But that operation belongs to an
entirely different category from that which we are now considering. None of
the factors on which the traditional system of British defence is based
were present. It was an operation over an open sea against a distant and
undetermined objective that had no naval defence of its own, whereas in our
own case the determining factors are permanent naval defence, an
approximately det