The King will open Parliament for the first time as monarch with a return to the full pomp and ceremony of the occasion, as the Queen re-wears her coronation dress.
Charles will don the Imperial State Crown, his lengthy crimson Robe of State and Admiral of the Fleet Royal Naval dress uniform, having travelled in a carriage procession from Buckingham Palace to the House of Lords in the Diamond State Coach amid great royal fanfare.
Camilla, wearing the famous George IV State Diadem for the first time, has chosen to re-use her coronation gown, designed by Bruce Oldfield, for her first State Opening as a Queen consort.
In recent years, the late Queen Elizabeth II mostly opted for a dressed down state opening – a functional coat, day dress and hat rather than the weighty crown and robes, often with a lower key arrival by car.
The changes were adopted due to her decreasing mobility as she neared 100, coupled with the pandemic, back-to-back State Openings due to a general election in 2019, and a diary clash with Ascot in 2017.
It has been seven years since a monarch wore the Imperial State Crown at a State Opening, the last time being in 2016.
Containing 2,868 diamonds, 17 sapphires, 11 emeralds, five rubies and 269 pearls, it weighs more than a kilogramme.
Charles wore the crown on his return journey to Buckingham Palace after his coronation.
Some 1,400 members of the armed forces will play a part in the proceedings in the first full military ceremony for a State Opening since before Covid.
Gun salutes will be fired from Green Park and the Tower of London, with troops from the Army, RAF and Royal Navy lining the route and the Household Cavalry Mounted Regiment including 124 horses providing a Sovereign’s Escort.
It is not the first time the King has undertaken the important constitutional duty of opening Parliament.
In 2022, as the Prince of Wales, he read the Queen’s Speech, with Elizabeth II delegating the task of opening Parliament to Charles and the then-Duke of Cambridge in their roles as counsellors of state in a historic move.
She pulled out of attending on the advice of royal doctors due to her continued mobility problems, and died four months later at the age of 96.
The late Queen stopped using the 26 steps of the royal staircase at the Sovereign’s Entrance at the opening in 2016, the year she turned 90, with Buckingham Palace saying the “modest adjustment” was made for her comfort.
But the King, who is a week away from his 75th birthday and has just returned from a busy tour to Kenya, and Queen Camilla are expected to return to using the stairs.
It is the first time a British King has opened Parliament for more than 70 years, since Charles’s grandfather George VI in 1950.
Charles was then a chubby-cheeked toddler, and stood on a wall at Clarence House, blowing kisses to his mother and grandparents as he watched the carriages in procession.
In 1951, the ailing monarch’s speech was read by the Lord High Chancellor.
By 1952, Charles’s mother was on the throne.
The prince, by then the heir apparent, was almost four at the time of the Queen’s first State Opening of Parliament.
The Queen, in her diadem, was photographed having a private word with her eldest son, learning over to speak to him as he looked up at her, on the steps of the Buckingham Palace quadrangle.
In 1967, just before his 19th birthday, Charles took part in a State Opening procession for the first time, travelling in a carriage with his sister Princess Anne and the Queen.
The Princess Royal will play a role in Tuesday’s state opening. As Colonel of the Blues and Royals, she will be in attendance as Gold Stick in Waiting, and will travel in the state landau.
Heir to the throne the Duke of Cambridge is away on a royal trip to Singapore and no other members of the royal family are expected to be present.
Camilla’s couture coronation dress – embroidered with motifs of her pet dogs and the names of her grandchildren – is a tailored ivory, coat-like dress, woven with antique gold and silver thread.
The late Queen reused her own coronation gown to open parliaments in Sri Lanka, Australia and New Zealand in 1954 and Canada in 1957.
Camilla will also wear the 5.5 metre-long crimson Robe of State, made for Elizabeth II’s coronation in 1953, which she wore for her arrival at the coronation.
The Diamond Diadem was worn countless times by Elizabeth II during her reign and is probably the most well recognised of all her pieces of jewellery.
Set with 1,333 brilliant-cut diamonds, it was made for George IV’s extravagant coronation in 1821 and Elizabeth II usually wore it for her journey to and from the State Opening.
She appeared wearing it on coins, banknotes and postage stamps.
It is the monarch’s duty as head of state to formally open each new session of Parliament amid tradition and customs dating back centuries.