The Pink Floyd (later just Pink Floyd) was a London psychedelic rock-pop band. Their first single was called "Arnold Layne", recorded January 29, 1967 and released in the UK on March 10, 1967.
It wasn't the first song I would look for backmasking on, but someone in a YouTube comment said there could be a Paul-Is-Dead clue in the video of the song and I listened to the song---and found backmasking.
The YouTube video of the song [see it at-- https://www.youtube.com/watch?v=EQTFRq1hjtM ] has The Pink Floyd assembling, disassembling, and dressing and undressing a 3-sectioned mannequin. The only direct hint the song is about a Beatle is at 0:30-0:31 in the video where the mannequin is "standing" on the trunk of a Volkswagen BEETLE.
The song is about a cross-dresser who steals women's clothes off clotheslines, is caught, and spends time in jail for doing it.
My theory about what happened to our Paul is that the British government wanted him out of the group and arranged some sort of plot to get their hands on him. It could have involved cross-dressing--or something else.
The song itself is a boring tune when you hear it forwards. Backwards, it has a very nice melody. So nice, I'm thinking The Pink Floyd was hoping it would be played backwards.
The producer of the song, Joe Boyd, said that the song was a complex recording with some tricky editing. Boyd said the instrumental section, for example, was a separate effort that was spliced into the final mix.
The instrumental "separate effort section" at 1:15-1:29 is a very reminiscent sound-alike of The Beatles' "Tomorrow Never Knows" from the Revolver album.
Put in context, here is what you hear backmasked on "Arnold Layne":
At 1:12-1:14 - Paul
1:15-1:29 - The "Tomorrow Never Knows" sound-alike segment
2:22 - Paul
2:25-2:27 - Paul would not
The Pink Floyd's Syd Barratt, who wrote "Arnold Layne", had mounting problems with the English social regime, so he probably knew enough about Paul's problems to want to comment about them.
P.S. In the post just preceding this one, I give you complete instructions on how to convert a YouTube video-audio into an mp-3 audio, upload it onto the popular Audacity audio tool and reverse it so you can listen to all the "Other Voices" tracks I've found that are telling a ugly tale about what happened to our Paul.
If you want to go digging into 1960's British groups' tracks and find other backmasking, please let me know what you find.