King Charles heard about his mother’s death while out foraging for mushrooms, a new book claims.

Queen Elizabeth’s final moments were recorded by her private secretary, Sir Edward Young, who was with her at Balmoral on September 8, 2022.

The historic document, which was shared by the Daily Mail, was not public until now and has been added to the Royal Archives.

He wrote: “Very peaceful. In her sleep. Slipped away. Old age. She wouldn’t have been aware of anything. No pain.”

This has been revealed in a new biography about the King called ‘Charles III: New King, New Court’, by royal writer Robert Hardman.

Charles, then the Prince of Wales, had been to visit his mother and had left the house to clear his head.

He had been out foraging for mushrooms and was on his way back when his senior aide took a call which delivered the news.

Charles was addressed for the first time as ‘Your Majesty’ and quickly boarded a helicopter back to Balmoral.

Shortly after the Queen’s death, a footman found a locked red box of paperwork at the end of her bed.

In it, staff found two sealed letters – one to Charles and the other to Sir Edward. The contents are unlikely to ever be made public.

It also contained her last royal order – her choice of candidates for the prestigious Order of Merit for “exceptionally meritorious service” across the Commonwealth.

The book is being serialised over four days with today’s extract revealing that Charles and Camilla spent a private hour with the Queen before she died.

It also said that Princess Anne and the Queen’s senior dresser Angela Kelly would alternate who sat at her bedside.

The book claims to have benefited from unrivalled access to the royal family, their close friends, staff past and present, top politicians and previously unseen papers in the Royal Archives.