Inspired by the statue of a soldier reading a letter on a platform at London’s Paddington Station, the project has received more than 3,000 letters so far.
These have come from schools, groups and individuals, including poet Andrew Motion, author Andy McNab, actor and presenter Stephen Fry, and the culture secretary Sajid Javid.
Throughout the project, London Paddington Station will be broadcasting a recording of young people reading extracts from their letters, including students from Fortismere School in north London. The extracts will be broadcast at intervals each day.
The project, created by authors Neil Bartlett and Kate Pullinger, is being run by 14-18 NOW, a First World War centenary programme hosted within the Imperial War Museums.
It is running until August 4 and at the end of the project the entire collection will be archived online at the British Library.
Letters have so far been received from children as young as four and adults as old as 89 and have come from as far away as China, Brazil, the United States, and the United Arab Emirates.
The letters speak of love and grief, bravery, politics, conscientious objectors, fear and death.
Ms Pullinger said: “Neil and I set out to create something original and inspiring, a memorial that would give everyone a voice.
She continued: “It’s clearly struck a chord with people and the kind of themes and stories coming through are fascinating. We’ll be featuring many of these as the memorial builds over the coming days.”
Other schools getting involved include Bohunt School in Hampshire which is devoting the entire school body to researching and writing 1,500 letters, which will be attached to red paper and laid out in the shape of a giant poppy on the school field next week.
Wallasey School in The Wirral will award the eight best letter writers with a trip to London to deliver 500 letters to the statue of the Unknown Soldier at Paddington.
For full details, visit www.1418now.org.uk/letter/