A moment in history, the proclamation is the official announcement of the Accession of the new monarch.
Huge crowds gathered in front of the Mercat Cross – dating back to the 14th century – to watch the proclamation of King Charles III.
It lies next to St Giles' Cathedral, a symbolic area as Her Majesty will lie in state here from today for 24 hours. Members of the royal family – including the King – will stand beside the coffin in a tradition known as the ‘Vigil of the Princes’.
Thousands lined the Royal Mile, with many holding up their phones and cameras to take pictures of the cross.
Following a fanfare of trumpets, the Lord Lyon King of Arms Dr Joseph John Morrow CBE QC made the proclamation and stated: “God save the King.”
The large crowd who waited eagerly for this to occur shouted back in celebration: “God save the King.”
Some booing was heard throughout the cheers after the official proclamation and one woman held an anti-monarchy sign. Police appeared and then took her away moments later, and the crowd began to applaud.
The national anthem was then sung, accompanied by music from the band, before the Lord Lyon King lead three cheers.
As the King’s Body Guard for Scotland and the guard of honour made their way towards Edinburgh Castle, the crowd broke out into a round of applause.
The procession included His Majesty’s State Trumpeters, representatives of the Society of High Constables in Edinburgh, the city officer, Macer to the Court of the Lord Lyon, heralds and “pursuivants” of Scotland, Lord Lyon King of Arms, and the City Mace and City Sword. Members of the City of Edinburgh Council wore red robes while leaving the City Chambers.
The King’s Body Guard for Scotland, known as the Royal Company of Archers, and the guard of honour marched from the Castle Esplanade to Mercat Cross for the occasion.
The procession returned to the Castle where the Lord Lyon read the second Proclamation.
One visitor who watched the proclamation said it was “pretty incredible” to witness the event.
Helen Smith, from Livingston, stood at the front of the barriers right next to the Mercat Cross.
She said: “I got here about 8am to get my spot.
“I came because it’s an event in history. I’ve only ever known one monarch, so I wanted to be here for it. Being quite close was pretty incredible, I could hear everything that went on. It was quite a spectacular sight to see.
“The whole atmosphere was a little bit surreal. With a large group of people, you expect a lot of noise but everything was really quiet as we just observed.
“My favourite bit was the first time we sang God Save The King, because we’ve only ever known singing God Save The Queen, so it’s a mind shift.”
Ann Hamilton, of Dumfries, added: “It might never happen again in my lifetime, so we just felt compelled to come today.
“We watched it on television the other day, but when it’s happening in the capital city of Scotland, we felt that we just needed to come.
“It was amazing seeing it live. Being here to witness a big part of history was just amazing. Looking at the costumes that the people were wearing, it’s just so historic. It’s important to keep traditions.”
Elsewhere, Wales Herald of Arms Extraordinary, Tom Lloyd, and the Lord-Lieutenant of South Glamorgan, Morfudd Meredith, read the proclamation of the new King in English and Welsh to the people of Wales at Cardiff Castle.
During heavy rain, the Norroy and Ulster King of Arms Robert Noel read the proclamation of the new King to the people of Northern Ireland at Hillsborough Castle following the death of the Queen.
A bell in the clock tower of the Court House at Hillsborough Castle gave a single chime on the stroke of 12 noon to signal the start of the proclamation.
Charles was formally proclaimed King in a historic ceremony at St James’s Palace on Saturday in London following a meeting of the Accession Council, during which he swore an oath to privy counsellors.
During a poignant and sombre meeting of the Accession Council, the King spoke movingly about his mother and the grief his family is experiencing, but said the “sympathy expressed by so many to my sister and brothers” had been the “greatest consolation”.
He began his momentous day by discharging the “sorrowful duty” of announcing the death of his “beloved mother”, and told the council: “I know how deeply you, the entire nation – and I think I may say the whole world – sympathise with me in the irreparable loss we have all suffered.
“It is the greatest consolation to me to know of the sympathy expressed by so many to my sister and brothers and that such overwhelming affection and support should be extended to our whole family in our loss.”
He was already King before the ceremony - under the terms of the Act of Settlement 1701, he automatically became so on the death of his mother.
The purpose of the Accession Council is a ceremonial one as it officially announces the name of the new monarch.