Composition and recording
The first demo was composed by Tim Rice-Oxley in about 2001. Rice-Oxley said that the song came from "hammering away on the piano" explaining "I was thinking of something like David Bowie's "Heroes", which you drive along to a really rocking beat. ... It was one of the first things we recorded for the album." It was first played on the guitar just before Dominic Scott left the band, and recorded as a demo the same year with a Yamaha CP70 instead of the guitar. Keane recorded the final version in 2003 at the Helioscentric Studios, Rye, East Sussex for the album. Keane also played this song at the historic concert Live 8 in London, along with the single "Bedshaped".
A demo version of "Somewhere Only We Know" was leaked into the Internet in 2004. This version features a different length (4:24) and an extra bridge. Chaplin's shout at the outro is removed.
"Somewhere Only We Know" is a traditional piano rock song. The piano is the most relevant instrument, due to its harmonic and rhythmic role. It is played in quavers throughout the whole song, holding the tempo and the rhythmic pattern. The studio version is recorded in 87bpm, and follows a 4/4 time signature, one of the most commonly used in traditional rock songs. It is in the key of A major. The song form can analyzed as "ABAB CBCB", a variation of the strophic form. The verse (A) chord progression is a plain (I-II-V), one of the most used chord progressions in music; the chorus (B) presents a (VI-III-IV-V) progression; the variation of the verse section (C) presents a (II-III-IV-V) progression.
The bass line was recorded by Rice-Oxley. When played live (up until 2007/8 with the arrival of bassist Jesse Quin), this song uses a pre-recorded bass, which is played in an Apple PowerBook G4. The 16-beat rhythm was made by Hughes. The song relies heavily on synthesizers, sampling and organ timbre, used to complement the harmonies in the song.