Plowden was born in
Strachur,
Argyll, the second child of Roger Plowden, a banker and landed proprietor, and his American second wife Helen. The Plowdens were, according to
Peter Jay, a long-established Roman Catholic family, originally established in
Shropshire about 1200. He returned after the War to the private sector, but then was appointed Chief Planning Officer to the Cabinet Office in March 1947. The group was called the Central Economic Planning Staff and Plowden headed it for over six years. In 1954 Plowden became the first chairman of the
United Kingdom Atomic Energy Authority (UKAEA). ==Korean War==