Queen Consort Camilla to be crowned at the coronation with controversial Queen Mary's crown

It's coronation day for King Charles III and Queen Consort Camilla, and beyond an extra bank holiday there's about to be a whole load of pomp and ceremony to go through.

While Charles became King immediately after the death of his mother, Queen Elizabeth II, he's being officially crowned today (6 May).

Alongside him is his wife Camilla, who became Queen Consort when Charles became King, and she will also be crowned during the coronation ceremony.

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Upon Charles' head will be placed St Edward's Crown, named after King Edward the Confessor and made for Charles II back in 1661 after the original crown was either sold off or melted down following the abolition of the monarchy in 1649 after the English Civil War.

St Edward's Crown was used for the coronations of James II and William III, but between 1689 and 1911 monarchs had other crowns commissioned for the ceremonies.

While Charles will be wearing that crown, Camilla will have Queen Mary's Crown placed upon her head during the coronation and it's a rather controversial item.

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It's the first time since the 18th century that a Queen is reusing a crown for a coronation, with Queen Caroline in 1727 wearing the crown that had been made for Mary, the wife of James II.

The crown is silver lined with gold and bears 2,200 diamonds, but the most controversial one which had been set into the crown won't be present.

When Queen Mary wore it for the coronation in 1911 (the same ceremony where wearing St Edward's Crown became traditional for the monarch) it bore the Koh-i-Noor diamond, over which there is a significant diplomatic dispute.

The diamond was officially ceded to Queen Victoria in 1849 as part of the treaty ending the Second Anglo-Sikh War, where the East India Company annexed the Sikh Empire during their conquest of the Punjab.

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India, Pakistan, Iran and Afghanistan have all demanded that the UK return the diamond to them at various points, while the British government has said parting with the diamond is 'non-negotiable'.

After Queen Victoria's death the diamond was set in the crown of Queen Alexandra for the 1902 coronation, then moved to Queen Mary's Crown in 1911 and then in 1937 it was placed in the crown Queen Elizabeth the Queen Mother wore at her coronation.

When Camilla wears Queen Mary's Crown today it will have neither the Koh-i-Noor or the replica, instead it has been reworked to include diamonds from Queen Elizabeth II's collection.