Maps of Scapa Flow's mature World War II defenses can hide the fact that those defenses were not ready at the start of the war. Blockships had decayed, shifted, been dispersed by storms, or been removed as navigation hazards, while the North Sea Mine Barrage had likewise disappeared or been cleared. Attention nominally shifted toward a possible Far Eastern war, yet the Treasury did not fund adequate defenses there either. The postwar assumption that another major European conflict had been ruled out helps explain why readiness seemed politically unnecessary. Scapa's vulnerability belonged to a wider failure to invest before European war again became imminent.
Notable Point · 1:57:54-2:02:35
Interwar neglect leaves Scapa Flow open again
The First World War defenses decayed between the wars, so the harbor entered 1939 far less protected than its later 1941 appearance suggests.