Miall joined the European Service of the BBC in early 1939. He took charge of broadcasts in German until 1942, when was seconded to the
Political Warfare Executive and sent to work on
psychological warfare in New York City and San Francisco. He returned to London in 1944, and then worked in the
Psychological Warfare Division of
SHAEF in
Luxembourg. He returned to the BBC in 1945, and was briefly a special correspondent in Czechoslovakia. He became the BBC's American correspondent from 1945 to 1953, covering nearly all of the
Harry Truman's presidency, and the first year of
Dwight D. Eisenhower's. Although based in Washington, D.C., he visited all of the then 48
U.S. states. His radio broadcasts made his voice a familiar feature of BBC news coverage. In June 1947, he reported a speech at
Harvard by
George Marshall, on reconstruction in Europe.
Ernest Bevin, then British
Foreign Secretary, heard the broadcast, and was spurred to press ahead with what became the
Marshall Plan for the nations of Europe to rebuild their economies after the war. When Miall returned to London, he served as head of "television talks" – documentaries and current affairs – at BBC television from 1954, assisted by
Grace Wyndham Goldie and based at
Lime Grove. During that period, programmes such as
Monitor,
Tonight and
The Sky at Night were created;
Panorama was relaunched; and
David Attenborough began his wildlife broadcasting career. Miall was promoted to assistant controller at the BBC in 1961, in charge of the planning for the new BBC television channel,
BBC2, which began broadcasting in 1964. He was appointed
OBE in 1961. After a period as Assistant Controller for Programme Services, Television, Miall returned to America in 1966 to run the BBC's New York office, in charge of editing news coverage and also selling BBC
costume dramas to American television channels. He returned to London in 1971 to become controller of overseas and foreign relations. He was involved in the establishment of the
Commonwealth Broadcasting Association. He retired in 1974. ==Later life==