In search of the blues

All You Need is Cash is a 1978 TV mockumentary written by and starring Eric Idle of the Pythons and his long-term comic collaborator Neil Innes. In the film, The Beatles are satirically reformed as The Rutles, but as well as taking an affectionate swipe at the Fab Four (re-dubbed The Prefab Four), Idle and Innes extended their comic vision to the British blues revival of the early Sixties.

In one sublime scene, the hapless reporter journeys to the Mississippi Delta to uncover the origins of T...