Which Beatles song has a backwards guitar solo that got banned by some radio stations?

The Beatles song with a backwards guitar solo that got banned by some radio stations is “Tomorrow Never Knows” from the 1966 album Revolver. The backwards guitar sound is actually a tape loop of George Harrison’s guitar playing sped up and reversed. The ban came from the lyrics, not the guitar trick — lines like “Turn off your mind, relax and float downstream” made some stations nervous about drug references.