The historic building where King Charles' accession is taking place: 5 points

King Charles III Accession: After the ceremony, an official will read the proclamation aloud from a balcony at St. James’ Palace.

King Charles III will be officially proclaimed Britain’s monarch on Saturday in a ceremony which will be broadcast live from the St. James' Palace, a royal residence in London. Charles automatically became king when his mother, Queen Elizabeth II, died on Thursday, but the accession council, senior politicians and officials who advise the monarch, meet this afternoon for the formal proclamation.

King Charles III Accession: Police officers on guard at St James's Palace in London. (AP)

After the ceremony, an official will read the proclamation aloud from a balcony at St. James’ Palace.

Here are 5 points on the St. James' Palace where the ceremony is taking place:

1. St James's Palace is the most senior royal palace in the United Kingdom which was built between 1531 and 1536 in red-brick. A fire in 1809 destroyed parts of the structure which have never replaced.
2. The palace is no longer the principal residence of the monarch but a ceremonial meeting place of the Accession Council.
3. The palace was built under the order of Henry VIII in the 1530s on the site of a leper hospital dedicated to Saint James the Less.
4. The palace was displaced in importance by the Buckingham Palace in the late 18th and early 19th centuries.
5. The move was formalised by Queen Victoria in 1837.