Thursday 8 September
12pm: Mark Stent, the executive producer, arrives at the Whitfield Studios in London where he will take delivery of 22 tracks.
1pm: Panic ensues when it emerges that Mercury prize-winners Antony and the Johnsons and Boy George's cover of "Happy Xmas (War Is Over)" has been lost en route from New York.
7pm: The first recordings begin, with Razorlight laying down "Kirby's House" in London and The Manic Street Preachers recording "Leviathan" in South Wales.
8pm: Emmanual Jal, one of Africa's hottest hip-hop stars, who was a child soldier in Sudan until a British aid worker rescued him, turns up in the London studio to record "Gua". Jal said: "I found it important to take part because of what they are doing for children in a war-torn place. I know how terrified they are. I'm asking people to pick up responsibility before another child picks up a gun." In Oxford, Radiohead produce"I Want None Of It" and in Liverpool, The Zutons record "Hello Conscience".
9pm: In Newcastle, Mercury Prize nominees Maximo Park are making the single "Wasteland".
10pm: Back in London, the technical team are working flat out as the tracks start to flood in. Time is running out to ensure the album is ready for download. In another London studio, Mercury-shortlisted Hard-Fi are recording "Help Me Please" while back in Liverpool, The Coral produce "It Was Nothing".
11pm: Belle & Sebastian are up until 4am in a Glasgow studio perfecting their track "The Eighth Station of the Cross Kebab House".
Friday 9 September
2am: In New York, Keane and Faultline work on their collaboration, a cover of Elton John's "Goodbye Yellow Brick Road".
6am: The international contributions are keeping the technical staff at full stretch. At the crack of dawn Stent takes delivery of the Gorillaz' contribution from Hong Kong.
7am: The Kaiser Chiefs have just three hours in Berlin to record a cover of "I Heard It Through The Grapevine".
8am: Four hours to deadline. The Magic Numbers are recording "Gone Are The Days" in London.
9.30am: Another recording is complete - Tinariwenp's "Cler Achel" is put together in Paris.
10am: Mylo's "Mars Needs Women" is recorded on the Isle of Skye, while in Brighton, Go! Team record "Phantom Broadcast". From Dublin, Damien Rice delivers "Crosseyed Bear" and in London, Bloc Party belt out "The Present".
12pm: Relief! A new version of Antony and the Johnsons and Boy George's track arrives via e-mail. Chris Martin wakes up in New York and approves a remix of Coldplay's "How You See The World" for inclusion. Elbow are one of the last bands to record a track, "Snowball", in Manchester.
By 6pm, the album was ready for download.
The record label Independiente, which is bringing out a CD version of Help on 26 September, advances War Child a six-figure sum, which is sent out to help children immediately.
* The War Child album is available for download on www.warchildmusic.com Single tracks cost 99p, while the entire album costs £9.99.