The new King will be formally proclaimed monarch at an Accession Council in St James’s Palace at 10am tomorrow (Saturday).
Charles automatically became King on Thursday on the death of his mother.
Today (Fri) on his return to London from Balmoral he met the Duke of Norfolk who is in charge of the Queen’s funeral and the accession.
The King earlier today expressed his wish that there be a week of mourning following the Queen’s funeral, the date of which has yet to be announced.
An Accession Council is normally convened in London within 24 hours of the death of monarch but Operation London Bridge, as the arrangements for the Queen’s death are known, is running 24 hours late.
In the past, the entire Privy Council is summoned to the Accession Council to oversee the formal proclamation of a new monarch.
But there are currently 700 – many of them past and present politicians which is unfeasible and the numbers will be capped at 200.
Those not invited can enter a ballot for a place.
The Accession Council is required to be held before parliament next meets, which is “as soon as practicable after the death of a sovereign”.
The Accession Council is presided over by the Lord President of the Council, who has ministerial responsibility for the Privy Council Office, and the latest holder of that office is former Tory leadership contender Penny Mordaunt who was named to the post, and as Leader of the Commons, this week.
The chosen Privy counsellors – without the King – will gather at St James’s Palace to proclaim the new sovereign, joined by Great Officers of State, the Lord Mayor and City Civic party, Realm High Commissioners and some senior civil servants.
If any of the counsellors summoned are not able to attend at short notice, the Council can still take place.
Camilla – the new Queen – and the Duke of Cornwall and Cambridge are privy counsellors and will be present.
When the meeting begins, the Lord President will announce the death of the sovereign and call upon the Clerk of the Council to read aloud the text of the Accession Proclamation.
It will include Charles’s chosen title, King Charles III.
The platform party – made up of Camilla and William, the Archbishop of Canterbury, the Lord Chancellor, the Archbishop of York, the Prime Minister, the Lord Privy Seal, the Lord Great Chamberlain, the Earl Marshal and the Lord President – will sign the Proclamation.
The Lord President will call for silence and read the remaining items of business, which deal with the dissemination of the Proclamation and various orders giving directions for firing guns at Hyde Park and the Tower of London.
King Charles will then enter and hold his first Privy Council.
He will make a personal declaration about the death of the Queen then take an oath to preserve the Church of Scotland because in Scotland there is a division of powers between Church and State.
He will read it out loud and sign two identical Instruments recording the taking of the oath, with his signature witnessed by Camilla and William, and others including the Secretary of State for Scotland and the Scottish First Minister.
Another oath, the Accession Declaration, to maintain the Protestant Succession, is normally made at the State Opening of Parliament.
Other business will be dealt with, including the use of the Seals, to “facilitate the continuity of government”.
Privy counsellors will sign the Proclamation as they leave.
The official record of proceedings will be published in a special supplement to The London Gazette.
After the Accession Council, the first public proclamation of the new sovereign will be read in the open air from the Friary Court balcony by the Garter King of Arms at St James’s Palace in the presence of the Earl Marshal and two of the sovereign’s Serjeants at Arms.
Trumpeters will play a fanfare from the balcony and gun salutes will be fired in Hyde Park and at the Tower of London at the same time.
The Proclamation will then be read at the Royal Exchange in the City of London.
It will also be read out publicly in other cities including Edinburgh, Cardiff, Belfast, Windsor and York, where the mayor traditionally drinks to the new sovereign’s health from a golden goblet.
The Privy Council dates back to the Norman invasion.
It advises the monarch on the duties of head of state.
The council also provides administrative support for the leaders of the Commons and Lords and has responsibility for the affairs of 400 institutions, charities and companies incorporated by royal charter.
It has a judicial role as the court of final appeal for UK overseas territories and crown dependencies and for a number of Commonwealth countries.
Members are required to take their meetings standing up throughout.