In 1936 he resigned from orchestral work to take up conducting and increase time for original composition. He had already had some occasion to conduct at Covent Garden in productions of the Sadler's Wells Opera and Carl Rosa Opera Company. He made a debut conducting the London Symphony in 1938.
In common with a number of young British musicians and artists, he left the country in 1939. He settled in Los Angeles, where he continued to conduct and to write film music.
After World War II he continued to live in Los Angeles, but frequently visited and worked in Britain, especially working with the London Symphony. He championed British music in both countries, specializing in music of the first few decades of the twentieth century, such as Bantock, Delius, Elgar, Vaughan Williams, and Walton. He made a very successful series of recordings of the complete Sibelius symphonies in the 1950s.
He also composed, including four short operas, two violin concertos, and other music. His best known composition was a work of light music, Vanity Fair.