During her 70-year reign, Queen Elizabeth II presided over every State Opening of Parliament, bar three.

She faced the tricky task of flawlessly reading the Government’s legislative programme while wearing the Imperial State Crown, which weighs 2.3lb (1kg).

The Mail’s Robert Hardman revealed in his book Charles III: New King. New Court that Her Majesty would ask for the crown to be delivered to her the day before the State Opening.

That would allow the late monarch to practise wearing the historic headpiece – which is encrusted with 2,868 diamonds and has 269 pearls, 17 sapphires, 11 emeralds and four rubies – and minimise the risk of mishaps on the day itself.

The Queen had a similar train of thought when preparing for her coronation in 1953. 

After her father King George VI died aged 56 in February 1952, the Queen had 16 months before her big moment in Westminster Abbey. 

Though it rained, the day saw few mistakes, thanks to copious preparation, including several rehearsals involving the Queen herself. 

King Charles recently recalled in a new film, Coronation Girls, how his mother would wear St Edward’s Crown, which is worn during coronations, around Buckingham Palace, including during the children’s bath times. 

The late Queen Elizabeth II delivering her speech in the House of Lords at the State Opening of Parliament in 1966

The late Queen Elizabeth II delivering her speech in the House of Lords at the State Opening of Parliament in 1966

The Queen attends the State Opening of Parliament in 1987 in the Imperial State Crown

The Queen attends the State Opening of Parliament in 1987 in the Imperial State Crown

The monarch delivering her speech to Parliament in 2008

The monarch delivering her speech to Parliament in 2008 

The documentary follows the story of 50 young women from Canada who travelled to the UK for the Queen’s Coronation after being sponsored by Canadian businessman and philanthropist Garfield Weston 

Charles recalled to the women: ‘I remember it all so well then, because I remember my sister and I had bath time in the evening.

‘My mama used to come up at bath time wearing the crown to practice. You have to get used to how heavy it is. I’ve never forgotten, I can still remember it vividly.’

It is a heart-warming story the monarch has shared before, including in a BBC tribute for the Queen’s Diamond Jubilee in 2012.

Charles said: ‘I remember my Mama coming, you know, up, when we were being bathed as children, wearing the crown. It was quite funny – practising.’ 

The Queen’s final State Opening of Parliament was in 2021, when she presided over the socially distanced event just one month after her husband Prince Philip passed away. 

Charles and Camilla were both present to watch as the Queen gave what turned out to be her final speech in the House of Lords. 

Just a month after Prince Philip's death, the Queen presided over the State Opening of Parliament for the last time in May 2021

Just a month after Prince Philip’s death, the Queen presided over the State Opening of Parliament for the last time in May 2021

The then Prince of Wales with the Queen after the State Opening of Parliament in 2019

The then Prince of Wales with the Queen after the State Opening of Parliament in 2019

Elizabeth did not wear the Imperial State Crown or ceremonial robes, however, and wore what royal officials described as ‘day dress’ instead – a coat and a hat – because of Covid restrictions making it less of a ceremonial event.

For her final years, the monarch’s Imperial State Crown was carried separately and placed on a table in the House of Lords.

In May 2022, just a few months before the Queen’s death, she had to pull out of the State Opening of Parliament on the advice of her doctor.

It was the first time in 59 years that the monarch would not preside over the event. She had previously only missed the event twice in her entire reign – in 1959 and 1963, while pregnant.

Charles sat in the consort’s throne, used by his father Prince Philip for decades, and delivered the Queen’s Speech in his mother’s place. 

Charles appeared emotional as he looked at his mother's crown before he read the Queen's Speech in his mother's absence in 2022, supported by his wife Camilla

Charles appeared emotional as he looked at his mother’s crown before he read the Queen’s Speech in his mother’s absence in 2022, supported by his wife Camilla

The King, wearing the Imperial State Crown like his mother once did, at the State Opening of Parliament earlier this year

The King, wearing the Imperial State Crown like his mother once did, at the State Opening of Parliament earlier this year 

The Imperial State Crown – the greatest symbol of British sovereign power and authority – was carried to Westminster in a limousine with Britain’s Crown Jeweller. 

Once at Parliament, it was placed on a velvet cushion on a table in front of Charles.

Poignantly, there was an empty space next to him, where the Queen’s slightly larger throne would usually be located.  

He would soon deliver this speech as King himself, in November 2023, following his mother’s death.