King Charles III has been officially proclaimed King at a ceremony in London this evening.
Although Charles became King the moment his mother died, the Accession Council ceremony is needed to make everything official.
The plan for King Charles's accession is called Operation Spring Tide, but many of the events follow traditions which date back hundreds of years.
The Accession Council began at 7pm AEST (10am UK time) in the State Apartments of St James's Palace in London, and will be followed by a public reading.
Most other readings will take place about noon local time, but all time references in this article are in AEST unless specified.
This story is no longer being updated. For the latest news on the Accession Council, visit this article about the proclamation or read updates in the ABC's live blog.
What is the Accession Council?
The Accession Council is a ceremony that's usually held within 24 hours of a sovereign's death.
It will be responsible for making a formal proclamation of the Queen's death, as well as marking the accession of King Charles.
The council includes privy counsellors — essentially, advisers to the sovereign — as well as high commissioners, senior civil servants, the Lord Mayor of the City of London and other figures.
Australia's high commissioner to the UK has been invited to attend.
The meetings will be overseen by the Lord President of the Privy Council, Penny Mordaunt, who is also leader of the House of Commons.
For the first time in history the Accession Council will be broadcast on television, including on ABC News.
The historic ceremony takes place in two parts.
What happens in Part I of the Accession Council?
Part I will take place without King Charles. This is where he will be officially proclaimed King, at 7pm.
When the meeting begins Ms Mordaunt will announce the death of Queen Elizabeth II and call upon the Clerk of the Council to read aloud the Accession Proclamation.
The privy counsellors will then proclaim Charles King, and formally approve a few other things relating to the proclamation.
The proclamation is then signed by senior figures including present members of the royal family, the British Prime Minister and the archbishops of Canterbury and York.
The number of attendees at the Accession Council will be capped at 200, according to British television network ITV.
At Queen Elizabeth II's ceremony on February 8, 1952, there were fewer than 200 people in attendance.
What happens after that?
King Charles will join Part II of the Accession Council, and hold his first Privy Council.
When the King enters the room business begins with his personal declaration relating to the death of the Queen.
Next he will take the oath that unites the churches of England and Scotland, known as the accession declaration — a tradition since King George I in 1714.
When can the public see a proclamation?
Once the Accession Council ceremonies are done, the first public reading of the proclamation will take place.
The Principal Proclamation will be read at 8pm tonight, from the balcony above the Friary Court of St James's Palace, by the Garter King of Arms, currently David White.
He will be accompanied by the Earl Marshal and other officials wearing traditional heraldic clothing.
The proclamation will be heralded by trumpeters of the senior army regiment, the Life Guards.
Amid the ceremony, gun salutes will be fired at Hyde Park and the Tower of London.
A carriage procession of heralds will then travel to Mansion House in the City of London, for a second public reading at the Royal Exchange at 9pm.
Large crowds are expected to turn out to see the pageantry unfold.
On Sunday, proclamations will also be read publicly in Edinburgh, Belfast, and Cardiff, at 9pm.
Before that, Australia's Governor-General will read it out in front of Parliament House in Canberra on Sunday at 12pm.
The Canberra reading will be open to the public, and followed by a 21-gun salute.
What about the coronation of King Charles III?
It may be more than a year before King Charles's coronation.
The coronation is a formal ceremony in which Charles will be physically crowned King.
Traditionally coronations are held at Westminster Abbey.
Queen Elizabeth II's coronation was on June 2, 1953, 16 months after her father's death.
ABC/Reuters
