ubmarines
and aeroplanes....

"If the Continental Powers secured the command they would possess the
great advantage of menacing us with a twentieth century
edition of the stroke Napoleon intended to deal against us from
Boulogne in 1805.

"To put the matter briefly; I hold that the Straits of Dover, regarded
as a military obstacle to the invasion of this country, will, in the
not far distant future, altogether lose their maritime character, and
the problem of their successful passage by an invading force will
present features somewhat resembling those involving the attack and
defence of great river lines or operations on the great lakes in a war
between Canada and the United States.

"The main object to be attained in trying to secure the passage of a
great river line is to gain possession of the opposite bank and
establish a strong bridgehead.

"In accordance with the views enunciated in this paper, I apply the
same principle to the Straits of Dover, and hold that the only
reliable defence against a powerful attack by hostile aircraft and
submarines in vastly superior numbers, is to possess a strong
bridgehead on the French coast with an effective means of passing and
repassing across the Straits which would only be secured by the
projected Channel Tunnel."

The bearing of all this upon the subject of the present chapter is
apparent. So long as the Germans were being driven back, whether by
frontal or flank attack, the Channel ports might be considered
comparatively safe; but on the particular night of which I am speaking
(September 16th) I had arrived at the conclusion that a frontal attack
was hopeless, whilst it began to appear that any threat against the
German flank would be effectually countered if not turned against
ourselves.

This, then, was my great fear. What was there to prevent the enemy
launching a powerful movement for the purpose of securing the Channel
ports, whilst the main forces were engaged in practically
neutralising one another?

From this time I sent constant and urgent warnings to London by wire
and by letter to look out for the safety of these same ports.

It was just about now that I began to conceive the idea of disengaging
from the Aisne and moving to a position in the north, for the main
purpose of defending the Channel ports and, as a secondary reason, to
be in a better position to concert combined action and co-operation
with the Navy.

At the moment of which I am speaking,