During the Second World War Jacob was one of several composers who contributed arrangements of popular tunes to the BBC comedy show "ITMA". Shortly after the war, on Boult's recommendation, Jacob was commissioned by a music publishing firm to orchestrate Elgar's Organ Sonata (1946). After a single performance in 1947 this version remained unplayed until 1988, when the Royal Liverpool Philharmonic Orchestra conducted by Vernon Handley recorded it for CD. Reviewing the recording, Edward Greenfield commented that dubbing the orchestrated version "Elgar's Symphony No. 0" was amply justified.