A second-term succession for Brown seems to depend on an Act of God

James Naughtie

"One is to win a referendum and take Britain into the single currency. The other is to win a third term.

"A second-term succession for Brown seems to depend on an Act of God, a runaway number 24 bus in Whitehall or a sudden change of heart on Blair's part."

But the book reveals the closeness of Mr Blair and Mr Brown's working relationship, peppered with constant private phone calls and meetings.

Third term

It says: "Blair still says he hopes Brown will succeed him, but the second term is meant to have its climax in the referendum and not in Blair's retirement.

"Then Blair would go for a third term.

"Brown, who would share the credit for a successful referendum and could hardly choose that moment to mount a coup d'etat, would have to decide whether he wanted to stay chancellor or step away from the government."

The author said Mr Blair, when privately asked if he had ever pledged to stand down in favour of Mr Brown, answered without a pause: "Absolutely not".

But Mr Blair is happy to defer completely to Mr Brown on areas such as economic policy, says the book.