Why Belgium mattered to British sea security

Belgium was a maritime-security problem for Britain as well as a legal trigger. The Channel coast and Dutch and Belgian ports figured in a long British habit of worrying about hostile fleets or armies north of Calais. Those approaches offered favorable tides, currents, winds, and ports for an invasion of Britain, giving events on the Belgian coast direct naval significance. The Schlieffen Plan rested on older assumptions because British attitudes had changed after the naval race, the Entente Cordiale, the Russo-Japanese War, the Navy Laws, and Kaiser Wilhelm's behavior.