He was the son of publisher Sir Stanley Unwin, of whom Severn wrote a biography in 1982, Fifty Years with Father.
Severn attended Abbotsholme School, Derbyshire, 1933–36, and worked for the League of Nations Secretariat, Geneva (1938), Unwin Brothers (printers), 1939, Blackwells (1940) and George Allen & Unwin (1941–43), having been declared medically unfit for the armed services.
The Warner family series followed (1947–52), featuring pheasants, ponies and country life.
has a musical youngster beating a native drum which transports children to a lost expedition to Africa twenty years earlier.
(Published in London by The Bodley Head unless indicated, selected titles in New York by Houghton Mifflin 1946–47 and thereafter Macmillan.