Industrial resilience depends on secure sea lanes

Reliance on continuing market purchases reduces the protection provided by state-held strategic stores. An import-dependent country must also protect the sea routes along which those purchases travel. Japan illustrates a naval force organised around the need to secure maritime supply. Allies can share that work when each contributes usable forces. European suppliers would face urgent requirements of their own during a European war, limiting Britain's ability to obtain reinforcements and materials from its immediate neighbours. Industrial mobilisation therefore also depends on reaching suppliers farther away.