The St Edward’s Crown has been removed from the Tower of London to be resized for the King ahead of the Coronation.
Buckingham Palace said the historic centrepiece of the Crown Jewels had been taken to allow for modification work to begin before the ceremony on May 6.
The movement of the priceless crown was kept secret until it was safely delivered.
Versions of the St Edward’s Crown are thought to have been used at the moment of coronation for British and English monarchs since the 13th century.
The current crown was made for Charles II in 1661, as a replacement for the medieval crown which had been melted down in 1649.
The original was thought to date back to the 11th-century royal saint, Edward the Confessor, the last Anglo-Saxon king of England.
It is St Edward’s Crown that appears in the royal coat of arms of the United Kingdom, the Royal Mail logo and in badges of the Armed Forces.
In a statement, Buckingham Palace said on Saturday: “St Edward’s Crown, the historic centrepiece of the Crown Jewels, has been removed from the Tower of London to allow for modification work to begin ahead of the Coronation on Saturday May 6 2023.”
The coronation will take place in Westminster Abbey, eight months after the monarch’s accession and the death of the Queen.
It is understood that the ceremony will include the same core elements of the traditional service, which has retained a similar structure for more than 1,000 years, while also recognising the spirit of our times.
Charles’s coronation is expected to be on a smaller scale and shorter, with suggestions that it could last just one hour.
It is also expected to be more inclusive of multi-faith Britain than past coronations but will be an Anglican service, with the Queen Consort crowned alongside Charles.
Guest numbers will be reduced from 8,000 to around 2,000, with peers expected to wear suits and dresses instead of ceremonial robes, and a number of rituals, such as the presentation of gold ingots, axed.
It comes after the Daily Mirror reported the King was planning a scaled-back and “less expensive” ceremony than the late Queen’s in 1953, which lasted around three hours, in acknowledgement of Britain’s cost of living crisis.
The late Queen’s coronation was a carnival of celebration, with half a million spectators lining her procession route on June 2.
Despite initial reservations, the late Queen eventually agreed to the TV cameras being present in Westminster Abbey to capture the historic event, with licence holders doubling in anticipation.
An estimated 27 million people in Britain alone watched the coronation live on their black and white televisions, and the images were beamed around the world.
The uncrowned Queen Elizabeth II set out from Buckingham Palace in the Golden State Coach, with the procession some 250 strong including traditional representatives from crown, church and state as it entered the abbey.
The Queen’s coronation dress, by couturier Norman Hartnell, was a white satin gown and was encrusted with diamonds, gold and silver bullion, seed pearls, crystals, pale amethysts and sequins to create a shimmering effect.
The service, which took place in front of a congregation of more than 8,000, began with the Archbishop of Canterbury Dr Geoffrey Fisher’s declaration to the assembled bishops: “Sirs, I here present unto you Queen Elizabeth, your undoubted Queen.”
After the ceremony, trumpets sounded and royal gun salutes were fired at the Tower of London and elsewhere.
Each Commonwealth prime minister had his own carriage for the longer return procession to the Palace and coronation chicken was invented for the foreign guests who were to be entertained afterwards.
The night came to an end as hundreds of thousands on London’s Victoria Embankment watched a lavish coronation fireworks display.