Rishi Sunak will become prime minister on Tuesday after a meeting with King Charles III.
The day begins with a farewell meeting hosted by Liz Truss with her Cabinet at 9am, Downing Street said.
She will then step out and make a statement in front of the famous black door of No 10 at around 10.15am.
Ms Truss will then take a short car ride from Downing Street to Buckingham Palace for an audience with the King, in which she will formally tender her resignation.
Once she has left, it is Mr Sunak’s turn to see the King at the palace. He will be appointed as the country’s next prime minister and asked to form an administration.
Mr Sunak will then head back to Downing Street to address the nation for the first time as prime minister at around 11.35am.
He will be the second prime minister since the monarch was crowned following his mother Queen Elizabeth II’s death in September.
Mr Sunak was declared winner of the Tory leadership contest on Monday afternoon, while the King was reportedly travelling to London, as he had previously planned, from the private royal estate of Sandringham.
Mr Sunak, 42, who was born in Southampton and is of Indian heritage, will become the country’s first non-white prime minister and the youngest in more than 200 years.
He was promoted to the role – without a usual vote by Conservative Party members – after a leadership contest that saw former prime minister Boris Johnson and House of Commons leader Penny Mordaunt stand aside.
Ms Truss’s predecessor Mr Johnson never formally declared his candidacy.
Mr Sunak, who served as chancellor in Mr Johnson’s government was the only candidate to receive more than 100 nominations.
Calls for a general election have been growing, with Tory MPs such as Nadine Dorries, Zac Goldsmith, and Sir Christopher Hope – supporters of Mr Johnson – joining demands that the nation be offered a say.
Sir Christopher said a general election should be called earlier than 2024, arguing it is the only solution for the next leader now the Conservative Party is “ungovernable”.
The MP for Christchurch in Dorset, told BBC Radio 4’s Today programme: “The best way they can get that respect is by winning a mandate with the people, and that’s why I think a general election is essentially the only answer, otherwise we’re just going to go from bad to worse.
“The party is ungovernable in the House of Commons and so we’re going to have continuing rebellions as we try to change policies and so on, and so I must say I’m very pessimistic, I’m very angry, and I feel that Boris has been let down once again and undermined by our parliamentary colleagues.”
