The 'thin crust' on the coast

30th June 1940: While mobile forces are kept in reserve inland, the troops kept on the coast must prepare to meet German invaders

A coastal gun on the English coast, June 1940.

All along the coast of Britain defence emplacements and fortifications were being rapidly established. The overall strategy was that any invasion force would be severely disrupted, hopefully destroyed, by the Royal Navy. The main British Land forces would be held inland and directed to atatck the landing poi…