Germany was supremely vulnerable to the Royal Navy choking off its lifelines. After the Battle of Jutland in 1916 had confined Germany’s High Seas Fleet to port, the tightening blockade became ever more effective, progressively causing the regulation of food prices, rationing, and finally the dreadful ‘Turnip Winter’ of 1917 in which its hungry population was reduced to eating the eponymous vegetable, and brewing ersatz coffee from acorns. 750,000 Germans starved to death, and the collapse in civilian morale led to social revolution, mutinies in the Fleet and Army, and finally to Germany suing for armistice terms.