London born and Jersey reared singer-songwriter Nerina Pallot composed this song on bass guitar during the week Britain entered the Iraq War in 2003. It was issued on downloads only in March 2005, and the following month saw a commercial release on Pallot's album Fires. After the album proved a commercial flop, Pallot toured as a support act for other artists, and in 2006 she signed to 14th Floor Records. On the back of performances on various TV shows her record company re-issued the song and this time it proved to be a hit peaking at #14 in the UK, Pallot's highest chart peak to date.
Rather than a straight protest song, it is more a reflection of Pallot's personal anxieties over friends she had grown up with joining the military. She recalled to The Daily Telegraph April 4, 2010: "There were friends who I'd always kicked a ball with and smoked joints with and I thought 'My God are they really going to do this? Are they really going to get into a tank and do this?' You look at the news and I was transfixed with fear. That song worked for me because I could see a face, I was picturing him putting on the gear and going. It was about my friend and what's going to happen to all of us. If you're going to do something creative, you can let your imagination go wild, but there has to be a kernel of truth in there. That's what I think good song writing should have."
The Marc Klasfeld directed video extended the song's war theme to a supermarket, where Pallot and other shoppers engage in a battle with food.
Pallot made four separate attempts at recording this song in different ways until she felt happy with it. She told CMU: "For me it's about presenting the song in its best possible light. The song should always, always come first."
The bedrock of David Guetta's Nicki Minaj-featuring single "Hey Mama" is a sample of "Rosie," a 1940s prison recording from folk archivist Alan Lomax that songwriter Esther Dean first showed the French DJ on YouTube.