The track, which was recorded in Ronnie Wood's "very luxurious" basement in 1974, features Page on guitar alongside Jagger, Keith Richards, Rich Grech and a handful of other players. "Scarlet" is among a few previously-unreleased tracks unveiled in advance of the Stones' deluxe edition of Goats Head Soup (due out this fall).
But Jagger says it was only when his memory was jogged that he recalled anything at all about the day "Scarlet" was recorded — let alone the fact that the song existed.
"Well, 'Scarlet', I've completely forgotten about this one," Jagger told BBC Radio. "...We just got together and started — it was Keith and me, and then Jimmy Page turned up for some reason, and we had various other musicians."
Most of the frontman's memories of the session are courtesy of Page himself. Jagger explained that he was under the impression Cream drummer Ginger Baker played on the song as well (a reasonable assumption because Baker and Grech were bandmates in Blind Faith a few years earlier), but Page set him straight.
"I didn't remember anything — Jimmy Page remembered everything, 'This person's done this; it wasn't Ginger Baker,' and I said, 'Alright,'" Jagger continued.
He added that he hasn't spoken to Page in a few years, "but he's very sweet, and he moved the whole thing."
In regards to why the Stones never released "Scarlet" or many other old recordings earlier, Jagger explained that there was lots of Stones material that was left by the wayside because the band didn't have a chance to complete it.
In a press released that came with "Scarlet," Richards explained that the recording was initially meant to be a demo. As such, The Rolling Stones may have intended to re-record it in a more professional environment with the rest of the band but never got the opportunity.
"The bottom line is that you didn't finish them," Jagger added of some of the newly-released old songs. "You're too lazy or you're on a deadline or so, and we don't have time to finish these other ones because we've got to go on tour or something, so that's how they get left behind really."
You can listen to "Scarlet" again in the player above.
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