Charles III will be formally proclaimed king at a historic ceremony at St James’s Palace on Saturday.
Flags lowered in mourning for the late Queen will fly full-mast after the Accession Council, which will be televised for the first time, the BBC reported.
A wave of further proclamations will take place across the UK until Sunday, when flags will return to half-mast.
It comes after the King pledged to follow his “darling mama’s” life of service in an emotional first address Friday.
He told the nation of his “profound sorrow” at the loss of his mother, praising her warmth, humour and “unerring ability always to see the best in people”. The 73-year-old monarch said he hoped that despite their sorrow at the Queen’s death, people in the UK and the Commonwealth “remember and draw strength from the light of her example”.
He promised to serve the nation with the same “unswerving devotion” as the late Queen had during her 70-year reign.
Charles became king the moment his mother died, but the Accession Council is held as soon as possible after death of a sovereign to make a formal proclamation of the successor.
At the council, which starts at 10 am local time, the King will make a personal declaration about the death of the Queen and make an oath to preserve the Church of Scotland – because in Scotland there is a division of powers between church and state.
Among those attending will be Camilla, Charles’s wife of 17 years who now has the title of Queen Consort, and the King’s son, William, the new Prince of Wales.
The first public proclamation is due to take place from the Friar Court balcony of St James’s Palace in London at 11 am, a moment that is usually accompanied by centuries-old pageantry, with trumpeters playing a fanfare and gun salutes fired in Hyde Park and at the Tower of London, the BBC said.
Here’s what will likely happen at the Accession Council:
As per the BBC report, historically, it is attended by all members of the Privy Council, a body of advisors to the sovereign that dates back to the time of the Norman kings. But with the membership standing at 700, mostly past and present politicians, only 200 are to be summoned.
They initially will gather at St James’s Palace without the King. Conservative MP Penny Mordaunt, appointed Lord President of the Privy Council by UK Prime Minister Liz Truss, will announce the death of the sovereign.
The clerk of the Council will read aloud the test of the Accession Proclamation, including Charles’ chosen title as king – which we know to be Charles III.
The proclamation will be signed by a group including the Queen Consort, the Prince of Wales, the Archbishop of Canterbury, the Lord Chancellor, the Archbishop of York and the prime minister.
The Lord President will call for silence and read the remaining items of business, dealing with the public proclamations and orders for the gun salutes at Hyde Park and the Tower of London.
The King will enter for the second part of the council, attended only by privy counsellors and make a personal declaration about the death of the Queen.
He will take an oath to preserve the Church of Scotland and signs two documents to record it, with the Queen Consort and the Prince of Wales among those witnessing his signature.
Privy counsellors will sign the proclamation as they leave.