War Production, that Italy would not be able to sustain a full year of continuous warfare until 1949. During the six-month fight against Italy, the Hellenic army made territorial gains by eliminating Italian salients. Greece did not have a substantial armaments industry and its equipment and ammunition supplies increasingly relied on stocks captured by British forces from defeated Italian armies in North Africa. To man the Albanian battlefront, the Greek command was forced to withdraw forces from Eastern Macedonia and Western Thrace, because Greek forces could not protect Greece's entire border. The Greek command decided to support its success in Albania, regardless of the risk of a German attack from the Bulgarian border. Hitler's decision to attack and British aid to Greece Britain was obliged to assist Greece by the Declaration of 13 April 1939, which stated that in the event of a threat to Greek or Romanian independence, "His Majesty's Government would feel themselves bound at once to lend the Greek or Romanian Government... all the support in their power." The first British effort was the deployment of Royal Air Force (RAF) squadrons commanded by Air Commodore John D'Albiac that arrived in November 1940. With Greek government consent, British forces were dispatched to Crete on 31 October to guard Souda Bay, enabling the Greek government to redeploy the 5th Cretan Division to the mainland. Hitler decided to intervene on 4 November 1940, four days after British troops arrived at Crete and Lemnos. Although Greece was neutral until the Italian invasion, the British troops that were sent as defensive aid created the possibility of a frontier to the German southern flank. Hitler's principal fear was that British aircraft based in Greece would bomb the Romanian oil fields, which was one of Germany's most important sources of oil. As Hitler was already seriously considering launching an invasion of the Soviet Union the next year, this increased the importance of Romanian oil as once Germany was at war with the Soviet Union, Romania would be the Reich'''s only source of oil, at least until the Wehrmacht presumably captured the Soviet oil fields in the Caucasus. As the British were indeed contemplating using the Greek air fields to bomb the Romanian oil fields, Hitler's fears that his entire war machine might be paralyzed for a lack of oil should the Ploești oil fields be destroyed were to a certain extent grounded in reality.