From "London Bridge is down" to "God save the King", the steps to crown King Charles III

New Delhi: Queen Elizabeth II's eldest son Charles, the rightful heir to the British throne, has become the King at the age of 73. The UK now has a new monarch in Charles, the former Prince of Wales.

Charles is the oldest person to ever assume the British throne.

As Charles is set to formally proclaimed King on Saturday, the steps which he will go through to be crowned King is interesting.

The Queen’s death has triggerred what is dubbed in Britain’s royal circles as Operation London Bridge – or the formal preparations and protocol that kicks in following the death of the monarch – with Operation Spring Tide, or the accession of her son and heir Prince Charles, the Prince of Wales, to the throne.

"London Bridge is down" is allegedly the way in which the death of the monarch would have been communicated to the Prime Minister, Liz Truss, by the Queen's Private Secretary, who will also tell the Cabinet Secretary and the Privy Council of senior officials and ministers.

The Foreign, Commonwealth and Development Office (FCDO) Global Response Centre is responsible for informing governments outside the UK where she is Head of State, followed by other Commonwealth nations including India. The day of her death is referred to as D-Day, with each subsequent day a countdown until the funeral, expected 10 days after her death.

It comes just days after she appointed her 15th Prime Minister, Liz Truss, at Balmoral Castle in Scotland, where she had been staying for her summer break. It marked a historic first for a British Prime Minister to not be anointed at Buckingham Palace in London after it was decided the journey would be avoided for the monarch, who has been suffering some mobility issues since last year and has been using a walking stick.

Charles’s accession will take place at St James's Palace in London, in front of a ceremonial body known as the Accession Council.

This is made up of members of the Privy Council - a group of senior MPs, past and present, and peers - as well as some senior civil servants, Commonwealth high commissioners, and the Lord Mayor of London.

At the meeting, the death of Queen Elizabeth will be announced by the Lord President of the Privy Council (currently Penny Mordaunt MP), and a proclamation will be read aloud.

The wording of the proclamation can change, but it has traditionally been a series of prayers and pledges, commending the previous monarch and pledging support for the new one.

This proclamation is then signed by a number of senior figures including the prime minister, the Archbishop of Canterbury, and the Lord Chancellor.

As with all these ceremonies, there will be attention paid to what might have been altered, added or updated, as a sign of a new era.

The King attends a second meeting of the Accession Council, along with the Privy Council. This is not a "swearing in" at the start of a British monarch's reign, in the style of some other heads of state, such as the President of the US. Instead there is a declaration made by the new King and - in line with a tradition dating from the early 18th Century - he will make an oath to preserve the Church of Scotland.

After a fanfare of trumpeters, a public proclamation will be made declaring Charles as the new King. This will be made from a balcony above Friary Court in St James's Palace, by an official known as the Garter King of Arms.

He will call: "God save the King", and for the first time since 1952, the national anthem will be played with the words "God Save the King".

Gun salutes will be fired in Hyde Park, the Tower of London and from naval ships, and the proclamation announcing Charles as the King will be read in Edinburgh, Cardiff and Belfast.

The coronation

The symbolic high point of the accession will be the coronation, when Charles is formally crowned. Because of the preparation needed, the coronation is not likely to happen very soon after Charles's accession - Queen Elizabeth succeeded to the throne in February 1952, but was not crowned until June 1953.

For the past 900 years the coronation has been held in Westminster Abbey - William the Conqueror was the first monarch to be crowned there, and Charles will be the 40th.

It is an Anglican religious service, carried out by the Archbishop of Canterbury. At the climax of the ceremony, he will place St Edward's Crown on Charles's head - a solid gold crown, dating from 1661.

This is the centrepiece of the Crown Jewels at the Tower of London, and is only worn by the monarch at the moment of coronation itself (not least because it weighs a hefty 2.23kg - almost 5lbs).

Unlike royal weddings, the coronation is a state occasion - the government pays for it, and ultimately decides the guest list.

There will be music, readings and the ritual of anointing the new monarch, using oils of orange, roses, cinnamon, musk and ambergris.

The new King will take the coronation oath in front of the watching world. During this elaborate ceremony he will receive the orb and sceptre as symbols of his new role and the Archbishop of Canterbury will place the solid gold crown on his head.