Mr Blair said his memoirs would be 'serious and thoughtful'

His account of 10 years as prime minister will be published by Random House, although no publication date has been set, it is reported.

The fee for the memoirs is expected to run into millions of pounds.

Mr Blair said he hoped they would "provide a serious and thoughtful, but also entertaining, reflection" on his time in Downing Street.

'Delighted'

The book will be published under the Hutchinson imprint in Britain and by Alfred A Knopf in the United States.

They are both part of the Random House group, whose chief executive Gail Rebuck is married to Lord Gould, Mr Blair's senior pollster during his time as Labour leader.

Ms Rebuck said: "We are absolutely delighted to be publishing Tony Blair's memoirs.

"He was an extraordinary prime minister, and this will be an extraordinary book.

"It is a great privilege for all of us to be working with him on this unique project."

It is thought Mr Blair's book is unlikely to appear for about two years.

A spokesman for the former prime minister would not comment on how much the deal was worth.

Random House published the diaries of Mr Blair's long-time communications chief, Alastair Campbell, in July.