Under the Iron Sea

The band called it a progression from Hopes and Fears, with electronic influences, and a sinister fairytale world gone wrong. Rice-Oxley kept writing through the world tour that ended in October 2005, and Chaplin said he had at least 50 tracks written by April 2006. The title comes from a line in Crystal Ball, "I've lost my heart, I buried it too deep, under the Iron Sea", and The Iron Sea is Keane's first instrumental. Hamburg Song, written around August 2004, deals with the strained relationship between Chaplin and Rice-Oxley, and Put It Behind You was written mainly by Hughes in mid-2004 after a break-up. The Frog Prince was written about another musician whom Rice-Oxley called talented but very arrogant. Broken Toy is the longest song in the band's catalogue.

The first three singles, Atlantic, Is It Any Wonder? and Crystal Ball, were premiered at a secret gig in London on 5 April 2006. Atlantic came out on 25 April as a download-only video single, directed by Irvine Welsh and filmed in black and white on a Sussex beach without the band. Kevin Godley directed the video for Is It Any Wonder?. Crystal Ball, released on 21 August 2006 as the third single, reached 20 in the UK. Rice-Oxley said it grew from a stretch on the road when he realised he had nothing to say and the band felt numb. Sanna Annukka, an artist from Brighton, designed the cover. Apple's Belgian iTunes store put the album on sale by accident for a few hours on 2 June 2006, and a US edition leaked on 5 June.

It opened at number one in the UK with 222,297 copies in its first week and at four on the Billboard 200 with 75,000, and has sold more than three million worldwide. Metacritic averages 63. Pitchfork's David Raposa gave it 4.1 and wrote that Keane "were slouching from the get-go", while crediting Green's production as rich. In 2008 a Q and HMV poll voted it the eighth best British album of all time.