Originally titled "Mouse, Bird, Dog," this song was first performed on acoustic guitar at Yorke's solo benefit gig for the Green Party in Cambridge in February 2010.
Like the other The King of Limbs tracks, "Separator'"s lyrics are cryptic. However, it appears to be the closest the album has to a love song - but more of a fantasy or dream about a lover than an actual event.
"Separator" is the closing track of The King of Limbs, which at just over 37 minutes is Radiohead's shortest album to date. However both some of the final lyrics ("if you think it's over, then you're wrong") and the song title itself gave credence to the idea that it was it was the first half of a two part release.