In 1941, the Soviets and the British jointly invaded Iran to secure the oilfields and supply lines and deny support for the Germans. By the 1950s, Britain was concerned by possible chaos in Iran and an invasion by the USSR. From 1951 Woodhouse was a MI6 agent in Tehran, operating under cover of a Foreign Office appointment. In 1952, he was ordered to arm tribesmen in northern Iran to resist any Soviet attack. He brought weapons into Iran, flying them from RAF Habbaniya in Iraq, for a "resistance" movement that did not exist as yet.