Powell was commissioned on the General List in 1940 but almost immediately transferred to the Intelligence Corps. He was soon promoted to captain and posted as GSO3 (Intelligence) to the 1st (later 9th) Armoured Division. During this time he taught himself the Portuguese language to read the poet Camões in the original; as insufficient Russian-speaking officers were available at the War Office, his knowledge of the Russian language and textual analysis skills were used to translate a Russian parachute training manual—a task he completed after 11 pm in addition to his normal duties, deducing the meaning of many technical terms from the context; he was convinced that the Soviet Union must eventually enter the war on the Allied side. On one occasion, he was arrested as a suspected German spy for singing the "Horst-Wessel-Lied". He was sent to the Staff College, Camberley.