Prime Minister Gordon Brown is starting his first full day in office with an overhaul of the Cabinet.Mr Brown, who has promised a "new government with new priorities", is expected to make long-time ally Alistair Darling his chancellor.
Environment Secretary David Miliband is expected to be promoted to foreign secretary. Douglas Alexander is the new international development secretary.
Alan Johnson is tipped for health and Jack Straw to be justice secretary.
Heavyweights
Mr Brown is expected to announce his senior ministerial appointments at about 1200 BST and to hold his first Cabinet meeting shortly afterwards.
Several heavyweight figures in predecessor Tony Blair's Cabinet are going.
John Reid is retiring as home secretary, Margaret Beckett is leaving the role of foreign secretary and Baroness Amos is no longer to be leader of the House of Lords, .
Patricia Hewitt, who has elderly parents in Australia, said she was quitting as health secretary, and resigning from the government, for "personal reasons".
It is being suggested that Education Secretary Alan Johnson will replace her.
Speaking on BBC Breakfast, Mr Johnson said: "You'll see lots of talent coming through, particularly the young talent that came into Parliament in 2001 [and] 2005.
"Now is their time for promotion and I think we'll see a lot of that," he said, but did not reveal what his new position would be.
It is thought unlikely that a replacement will be announced for outgoing Deputy Prime Minister John Prescott.
Lib Dem meeting
Meanwhile, Mr Straw, who oversaw Mr Brown's campaign to become Labour leader, is widely tipped to replace Lord Falconer as justice secretary.
Before entering 10 Downing Street on Wednesday, the new prime minister said: "I will try my utmost. This is my promise to all of the people of Britain. And now let the work of change begin."
He met Liberal Democrat peer Baroness Williams in the Commons but a government source said no ministerial role would be offered to her.
He has already asked former Lib Dem leader Lord Ashdown to become Northern Ireland secretary, but this was refused.
After stepping down as prime minister, Mr Blair also quit as MP for Sedgefield to become a Middle East peace envoy on behalf of the EU, US, UN and Russia.
