Most often in the role of orchestral or choral arranger, Barham also contributed to albums such as the Beatles' "Let It Be", John Lennon's "Imagine" and Gary Wright's "Footprint" in the early 1970s. His projects as a music producer during the same period included three albums by progressive rock band Quintessence, and he has worked on film or TV soundtracks for directors Otto Preminger, Alejandro Jodorowsky and Jonathan Miller. Other artists with whom Barham has worked include Elton John, André Previn, Phil Spector, Roger Daltrey, Yoko Ono and Jackie Lomax.