From Baker's Biographical Disctionary of Musicians
Rankl, Karl, Austrian-born English conductor and composer; b. Gaaden, near Vienna, Oct. 1, 1898; d. Salzburg, Sept. 6, 1968. He was a pupil of Schoenberg and Webern in Vienna; from them he acquired a fine understanding of the problems of modern music. He occupied various positions as a chorus master and an opera coach in Vienna; served as assistant to Klemperer at he Kroll Opera in Berlin (1928-31); then conducted opera in Graz (1932-37) and at the German Theater in Prague (1937-39). At the outbreak of World War II, he went to England and later became anaturalized subject; was music director at Covent Garden in London (1946-51), the Scottish National Orch. in Glasgow (1952-57), and the Elizabethan Opera Trust in Sydney (1958-60). He composed an opera, Deidre of the Sorrows (won the Festival of Britain prize, 1951, but was not perf.); 8 syms.; an oratorio, Der Mensch; many choral works.
See also http://www.schoenberg.at/1_as/schueler/wien/Rankl.htm
http://www.rrz.uni-hamburg.de/musik/exil/texte/quartette/rankl.html