This song traces The Libertines' story, from their early days to their tabloid notoriety. Co-frontman Carl Barat told Q magazine it's about, "risking everything, going out to find the devil at the crossroads."
He added: "It's very much a cautionary tale."
Co-frontman Peter Doherty explained to NME that the band had been carrying around the melody since the very beginning of the group, but decided to "finally put it to bed."
"We scuttled off and did the lyrics one afternoon," he said. "Then everyone decided it needed a chorus, and Gary and John mucked in for that."
The song features the sound of a motorbike engine revving. Producer Jake Gosling told NME that he had encouraged the band to experiment: "For me, it's capturing magic. Carl was saying 'What about a motorbike?' so I said 'Brilliant! Let's wheel it in and record it!' He was there revving it up in the studio and beeping the horn and all this sort of stuff," he said. "Creating and having fun and being able to do those things in the studio that I think they haven't been able to do before was a real jump for them."
"Sloop John B" is a traditional West Indian folk song, and it was a huge hit for The Beach Boys in 1966. They tweaked the lyric, "This is the worst trip since I've been born" to "...I've ever been on" as a wink to acid culture.