 Following Germany's invasion of the USSR in June 1941, the United Kingdom and the Soviet Union became allies.Although a neutral nation, Reza Shah Pahlavi had brought Iran closer to Germany.This concerned the British who feared that the Abadan Oil Refinery, owned by the Anglo-Iranian Oil Company, might fall into German hands — the refinery produced eight million tons of oil in 1940 and was thus a crucial part of the Allied war effort.