Former Prime Minister Tony Blair will donate his advance and all of the proceeds from his upcoming memoirs to the Royal British Legion.
The money from A Journey, which will be published on 1 September, will go towards the charity’s Battle Back Challenge Centre, a rehabilitation centre for seriously injured service personnel.
Blair’s advance for writing the book has been reported as £4.6m, although a spokesman for the former premier would not confirm the figure.
The spokesman added in a statement: "In making this decision, Tony Blair recognises the courage and sacrifice the armed forces demonstrate day in, day out.
"We have been consulting with a number of people and organisations to decide the best support he can give. There is one project consistently highlighted: The Royal British Legion’s Battle Back Challenge Centre."
The charity has set a fundraising target of £12m for the centre, which is due to open in summer 2012.
Chris Simpkins, director-general of the Royal British Legion, said: "Mr Blair’s generosity is much appreciated and will help us to make a real and lasting difference to the lives of hundreds of injured personnel."