How the fall of France transformed the Mediterranean war

France's defeat brought the enemy closer to Britain and gave German submarines access to Biscay bases, making Atlantic operations much easier. At the same time, the French fleet ceased operating as an ally in the western Mediterranean and Italy entered the war on Germany's side. Britain therefore had to retain heavy units in home waters while protecting Malta, supporting the North African campaign, and maintaining communications with Egypt and the eastern empire. Routes that had depended on a neutral or friendly Mediterranean could no longer be taken for granted. The land campaign against Italy and then Germany further tied maritime supply to events ashore. France's collapse rapidly redrew naval geography, changed fleet allocation, and exposed an empire's distant communications.