British security policy favored a divided opposite coast, since control by several powers preserved trading options and reduced the danger of one hostile state holding every nearby port and invasion approach. The aim was a peaceful division of power, since wars among those states also disrupted trade. The plan for a European war expected France to fight on land while Britain reinforced it and protected Belgium, broadly repeating the First World War pattern. France's collapse destroyed that assumption. Existing British small-craft designs now had to face E-boats as well as Danish, Dutch, and Belgian patrol and torpedo craft taken over by Germany.
Notable Point · 24:13-27:29
France's fall reshapes Channel security
British strategy expected France to remain in the war; its collapse made the opposite shore a direct security problem and exposed shortcomings in available coastal designs.