In the Near and Middle East the Allies were faced with the crucial problem of protecting their lifelines. In April 1941, British troops moved into Iraq to suppress a Nazi-inspired coup and secure the valuable oil fields there. When the French Vichy Government allowed the Germans to use Syria (a French mandate) as a base, British troops, together with Free French comrades, entered Syria from Iraq in June and imposed an armistice giving Britain control over Syria and Lebanon. In August both Britain and the USSR (by then a British ally) occupied Iran and forced its pro-German ruler, Reza Shah Pahlavi, to abdicate on Sept. 16, 1941, in favor of his son Muhammad Reza Shah Pahlavi. Reza Shah was sent out of the country.
North African Campaign, 1940–1941
Italy's entrance into the war changed the entire scene in the Mediterranean region; previously a minor theater of war, the area now became tremendously important. Mussolini had made no secret of his desire to construct a huge Mediterranean empire at the expense of the British. He planned to move one army northward from Italian East Africa and send a second army eastward into Egypt from Libya. He hoped to catch the British in an African vise and eliminate them from the shores of the Mediterranean.
Mussolini's first step was to overrun British Somaliland, defended only by a small garrison, in August 1940. But his triumph was short-lived, for by the next summer the British not only had recaptured that territory but had driven the Italians from their East African possessions, thereby securing the Suez Canal from an attack from the south.
Meanwhile, in September 1940, Mussolini moved a second army of Italians and North African troops across the Libyan border to establish themselves about 100 km (60 mi) inside Egypt. The British struck back in December in a surprise attack that carried them halfway across Libya by early February 1941. Once again Mussolini needed Hitler's assistance. In March 1941, Germany's Afrika Korps, commanded by Gen. Erwin Rommel, arrived at Tripoli. By mid-April, Rommel had reconquered all of Libya except Tobruk; his exploits earned him the nickname the "Desert Fox."
At the same time, Mussolini's hopes of making the Mediterranean an Italian lake were being dashed. The British maintained their command of the Mediterranean by smashing a large part of the French fleet at Oran, Algeria (July 1940), to ensure that it would not fall into Axis hands (unlike other French fleets, it had refused to submit to seizure by the British after the fall of France). The British also damaged the Italian fleet at Taranto, Italy (November 1940), and at Cape Matapan, Greece (March 1941).
The Atlantic, 1940–1941
The defeat of France was a great boost for German sea power as French ports became bases for the U-boats. The effectiveness of U-boats increased during the autumn of 1940 as they began to move in wolf packs, long lines of submarines acting in concert to overwhelm enemy convoys. In addition, the Germans made use of long-range bombers. As a result British shipping losses increased dramatically during the last half of 1940.
Although the introduction of the small but useful corvette-class ship added to convoy protection, and the United States helped bolster the convoy system by agreeing (September 1940) to exchange 50 overage destroyers for 8 air bases in British possession, the number of U-boats was increasing, and British losses continued to mount sharply in 1941. New ships were being built in Britain, but the rate of loss exceeded the production rate. By the spring of 1941 the number of sinkings reached such a critical level that Churchill called the seaborne attacks the Battle of the Atlantic. Still the British managed to keep the sealanes open for desperately needed supplies from the United States.
In the midst of the havoc wrought upon Britain's trade, the country won an important morale-boosting victory. On May 24, 1941, the German battleship Bismarck, the pride of Hitler's navy, sank the British battle cruiser Hood off Greenland. On May 27, however, the Bismarck was intercepted by a British task force while returning home and was sent to the bottom of the sea.