Today's timetable9am-midday: The outgoing prime minister spends his last few hours in 10 Downing Street.
Midday: Tony Blair is driven to the Houses of Parliament for his 318th and final joust at prime minister's questions. He is expected to be wearing the same "lucky" brogues he has worn for the past 13 years at the session.
12.30pm: That historic confrontation over - and doubtless with a big send off from the 351 Labour MPs behind him - Mr Blair heads back to Number 10. He is usually driven the short distance down Whitehall.
12.30pm-1pm: Mr Blair - and family - say goodbye to Downing Street staff in the cabinet room. Many of his staff, such as chief of staff Jonathan Powell, are leaving with him.
1pm: Mr Blair leaves Downing Street for the final time with his wife, Cherie, and is driven the five minute journey to Buckingham Palace for his audience with the Queen.
1.15pm: After arriving in the quadrangle of Buckingham Palace, Mr Blair will be ushered inside for an entirely private audience with the monarch as Cherie Blair waits in an anteroom. Having met the Queen once a week for 10 years, this will be their final face-to-face meeting as head of state and head of government. He will be introduced to the Queen as prime minister - the last time he will be addressed as such.
At the end of their meeting, Mr Blair will formally resign as prime minister. Contrary to speculation, this does not involve the handing over of any physical seal of office. No letter is necessary: his word will be enough.
Mr Blair will leave the palace an ordinary citizen - although he will retain police protection and will be allowed to stay at Chequers for several days until his new London home in Connaught Square is ready.
Immediately after he is driven away from Buckingham Palace, it is thought he will fly to his Sedgefield constituency, where he is set to announce his resignation from parliament with immediate effect.
For a few minutes the country will have no prime minister.
As Mr Blair leaves Buckingham Palace, the Queen's private secretary will ring the office of the Labour leader, Gordon Brown, instructing him - wherever he is - to attend her majesty immediately. In reality, of course, Mr Brown will be waiting for the call.
Mr Brown is chauffeured up the Mall to the Palace, where the Queen will appoint him prime minister and ask him to form a government. He will immediately take on Mr Blair's protection squad.
2pm: The new prime minister is driven back to Downing Street. It would be unlikely he will enter Number 10 without speaking to the mass of reporters outside.
There will already be decisions he has to take. He has no need to move his lodgings: he already lives above the shop, because the Blairs lived in the larger home of No 11. He will then begin forming his cabinet.
Why is Tony Blair stepping down? (BBC)
Gordon Brown answers your questions (The Independent)
Bom-dia Mundo!