Rishi Sunak will become the UK's 57th Prime Minister this morning - making him the first leader to be appointed by King Charles III.
The 56th, Liz Truss, will chair a final Cabinet meeting at around 9am before heading to Buckingham Palace to tender her resignation just over an hour later.
Mr Sunak, was yesterday selected as the new Tory Party leader after Boris Johnson and then Penny Mordaunt pulled out of the race for Number 10.
The outgoing PM is expected to make the short trip to the Palace at around 10.15am, bringing her short but disastrous spell in charge to an end.
Mr Sunak will follow her in, and will be asked to form a government by the King, performing the historic duty for the first time.
Mr Sunak will be the third Tory PM this year after Mr Johnson and Ms Truss were each forced out of office by rebellions in their own party.
He is expected to give a speech from Downing Street at around 11.35am, having spoken for just 86 seconds in a brief address earlier.
It is not yet confirmed when Mr Sunak will announce his new Cabinet, but he is not expected to delay, having earlier told backbench MPs that his government must hit the ground running.
He has ruled out an immediate General Election, despite voters clamouring for the chance to go to the polls.
Ms Truss announced her resignation on Thursday after 44 days in charge, during which time markets descended into chaos and Tory popularity plunged even further.
It has not yet been confirmed if she will make a speech in Downing Street before departing, but previous Prime Ministers have opted to do so.
After her audience with the sovereign ends, Mr Sunak will be invited in and the office will change hands - without any consultation with the public.
It is a process many will be familiar with, having gone through it just over six weeks ago.
On September 6, disgraced Mr Johnson flew to Balmoral to formally tender his resignation to the Queen.
A short time later Ms Truss met the monarch, becoming the 15th Prime Minister of her reign. Sadly she was also the last, as the sovereign's death was confirmed just two days later.
This means it now falls to her son to perform the duties required for the latest shift of power.
Once Ms Truss's discussion with the King ends, Mr Sunak will enter the Palace gates to be greeted in the courtyard by an equerry and the monarchs Private Secretary.
He will wait in an antechamber to be briefed - generally by the Lord Chamberlain - before entering the King's private apartments.
No one else will be present during this audience. The new PM will be appointed under the monarch's Royal Prerogative.
The King will invite Mr Sunak to form an administration.
It is expected that once this is done, the new Prime Minister will give an address from outside 10 Downing Street.
This is what Ms Truss did, taking advantage of a brief interlude in heavy rain to tell the British public: "We shouldn’t be daunted by the challenges we face.
"As strong as the storm may be, I know that the British people are stronger."
