Inside story of the late Queen's final farewell: How Her Majesty 'wouldn't have been aware of anything' when she painlessly 'slipped away' - as contents of never-before-seen memo of her last moments are revealed

• Sir Edward Young recorded in memo that the Queen's death was 'very peaceful' 

Queen Elizabeth's last moments were recorded by her most senior member of staff in an extraordinary - and deeply moving - memo which can be revealed by the Daily Mail for the first time today.

Sir Edward Young, her devoted private secretary, who was at Balmoral when Her Late Majesty died on September 8 2022, noted: 'Very peaceful. In her sleep. Slipped away. Old age. She wouldn't have been aware of anything. No pain.'

The existence of the historic document, now lodged in the Royal Archives, has not been made public until now.

It forms part of a remarkable insider account of the late monarch's bravery, diligence and devotion to duty in her last hours contained in a fascinating new biography of the King, 'Charles III: New King, New Court. The Inside Story' by the Mail's esteemed royal writer Robert Hardman.

The book is being exclusively serialised over four days from tomorrow.

The biography also reveals how, shortly after Sir Edward wrote his note, a footman brought a locked red box of paperwork found at the late Queen's deathbed.

When it was opened, staff discovered two sealed letters: one to her son and heir, now King Charles III, and the other to Sir Edward himself.

While their contents are unlikely ever to be made public, the existence of the letters shows that Elizabeth, 96, quietly recognised her time on this earth was at an end.

The box also contained her final piece of paperwork and last royal order: her choice of candidates for the prestigious Order of Merit for 'exceptionally meritorious service' across the Commonwealth.

'Even on her deathbed, there had been work to do. And she had done it,' Hardman writes of her unparalleled devotion to duty.

Other astonishing revelations in today's extract reveal:

• Despite fears for her health the late Queen's death was so sudden that Charles had to undertake a last-minute dash to Balmoral by helicopter, reading his 'London Bridge' notes [the long-arranged plan of action following her death] on the way. Staff didn't even have time to get his car ready to greet him.

• The King and Queen Camilla spent an hour with Her Late Majesty privately before she died.

• Princes Anne and the Queen's senior dresser and confidante, Angela Kelly, alternated at her bedside, along with the Rev Kenneth MacKenzie, a long-serving minister at nearby Crathie Kirk, who read to her from the Bible.

• Charles called both of his sons personally, urging them to travel up to Scotland as soon as possible in order to say their goodbyes. At that point he believed the Queen still had days, not hours, to live

• Charles, who had gone out to gather mushrooms and clear his head after seeing his mother, received the news that she had died as he was driving back to Balmoral when his most senior aide took a call. Charles pulled over and was addressed for the first time as 'Your Majesty' before calmly putting the car into gear and driving on.

• When Charles called William via the palace switchboard to break the news to him he was forced to tell the operator simply 'it's me' as he suddenly realised he couldn't reveal that he was king, yet.

• The King did try to repeatedly call his younger son to break the news to him personally, but Harry was already in the air and he could not get through.

Charles III by Robert Hardman charts the dramatic story of transition at the very top, looking at at the challenges that have faced the new king in his first year on the throne including family dramas, political crises and questions about the future of the monarchy.

The book boasts unrivalled access to the Royal Family, their close friends, staff past and present, top politicians and previously unseen papers in the Royal Archives.

It also describes the vital role played by Queen Camilla, the King's relationships with Prince William and Prince Harry, his plans for reforming the monarchy and his evolving position on the world stage.