Tony Blair offered to step down before the next election if Gordon Brown backed plans to join the euro, former minister Clare Short has claimed.
Brown refused to put ambition before UK interests, says Short
Mr Brown refused because he would not put his own ambitions before Britain's economic interests, she says in her new book serialised by The Independent.
Ms Short - an ally of the chancellor - said Mr Blair used her as a go-between to discuss the matter.
Mr Brown also feared he would be ousted after the Iraq war, Ms Short adds.
"He said they planned a short war and a reshuffle. He felt very much under pressure and believed they wanted to move him from being chancellor," she writes in her book, An Honourable Deception?
Mr Brown had refused to take any other cabinet post, Ms Short says in The Independent extract.
Ms Short also claims the prime minister told her on a trip to West Africa in 2002 that he did not want to serve a third term.
Last month, Mr Blair announced he would stand for a third term and serve the whole term if elected.
But Ms Short said that Mr Blair "wished Gordon would work more closely with him so that he could make progress on the euro and if he did so he would be happy to hand over to Gordon".
"He made it quite clear that he wanted me to tell Gordon what he had said."
When she passed on the message to Mr Brown, he said two other ministers had given him the same message.
"Gordon's answer was, firstly, that such deals were not worth talking about because previous agreements had not been kept," said Ms Short.
"Secondly, he would not contemplate recommending that we join the euro in order to advance his own position rather than advance the economic interest of the country."
She said in a second meeting in September last year Mr Blair told her Britain must join the euro before the election, and that what he had proposed in West Africa was still on offer.
Short says the reunion with her son has been a 'joy'
Ms Short also indicated the chancellor had reservations about giving his full public support to Mr Blair over the Iraq war.
She said deputy Prime Minister
John Prescott "brought them together" over dinner and Mr Brown "agreed to get involved and help" Mr Blair.
Ms Short also claimed Mr Brown said he was "sick of fighting against bad proposals" by Downing Street, such as removing child benefit from parents of truants - which he crushed - as well as university top-up fees, which went ahead.
She also talks about the reunion with her son whom she had had adopted while she was at university.
"My son's return has healed a hole that has been at the centre of my life ever since he left. His existence is a source of enormous joy and happiness for me," she writes.
"Our story also led to a big growth in adopted children seeking contact with their natural parents."