The service had to learn fast. It soon became clear that the Germans would not provide an opportunity for a major battleship-to-battleship fleet action along the lines of Jutland, but that submarine warfare and surface raiders were to be just as effective at undermining the British war effort. The Royal Navy was expected to be active in the North Atlantic and in British waters, and then, after the Soviet Union was invaded by Germany, it had to protect the Arctic convoys. Meanwhile, it also had to keep control of the Mediterranean, alone after the fall of France, supporting ground forces in North Africa and then in Greece, send convoys to Malta and disrupt the Axis supply lines both in the Mediterranean and off the coast of Norway, before facing the Japanese in the Far East.