Henry Allingham is one of three known survivors of WWI in the UK
The oldest man in Britain and one of the last survivors of World War I has co-written a book about his life.
Henry Allingham, who celebrated his 112th birthday in June, launched Kitchener's Last Volunteer at the RAF Club in Piccadilly, central London.
Mr Allingham, from Sussex, is the last surviving original member of the Royal Air Force, formed in 1918.
He was in tears as he spoke of his appreciation for the comrades who lost their lives in the Great War.
"I am here today not for me, but for all those who gave their lives on our behalf," he said.
"Thank goodness for those people. I could never thank them enough.
"If it wasn't for them, our privileges would have been destroyed. We probably would not even be here now."
For many years, Mr Allingham lived in Eastbourne but when his eyesight began to deteriorate, he moved to St Dunstan's care home for blind ex-service personnel near Brighton.
He was joined at Tuesday's book launch by his friend and co-author, Dennis Goodwin, founder of the First World War Veterans' Association.
Paying tribute, Mr Goodwin said Mr Allingham was a recluse when he first met him.
"I think he has done so well now because the more you engage people and focus attention on them, the more they develop a will to live," he said.
"And that's the case with Henry. If he had been allowed to vegetate he would have disintegrated."
Mr Allingham joined the Royal Naval Air Service in September 1915 before transferring to the RAF in April 1918.
He is just one of three known UK survivors from the First World War.