Following Germany’s invasion of the USSR in June 1941, Britain and the Soviet Union became allies. Britain and the USSR saw the newly opened Trans-Iranian Railway as an attractive route to transport supplies, including oil, from the Persian Gulf to the Soviet Union. Britain and the USSR used concessions extracted in previous interventions to pressure Iran (and, in Britain’s case, Iraq) into allowing the use of their territory for military and logistical purposes. Increased tensions with Britain led to pro-German rallies in Tehran.
