The Mellow Yellow hitmaker set the pace for the wave of experimental psychedelic music being recorded during the Fab Four's heyday, but as he worked on what was to become one of his most famous albums, he received a stern warning in the studio.

Famed British producer Mickie Most knew Leitch was close friends with The Beatles and he was convinced MCCartney would "sponge" any good ideas he heard and use them in his own work.

Leitch tells Mojo magazine, "So we made five tracks. And Mickie says, because he knows I'm hanging out with The Beatles, 'Don't play this to MCCartney.' Because there's a sponge going on. The Beatles were spongeing beautifully all forms of popular song. But I'm doing my thing, and Mickie says, 'Don't play it to Paul' - and of course I did, because I wanted to."