Anna Keay, a historian whose most celebrated book is about Britain’s republican period, has been confirmed as Queen Elizabeth II’s official biographer.

Keay will interview members of the royal family and the late queen’s friends and servants. She will also have access to the monarch’s personal and official papers held in the royal archives.

Keay, 51, has worked in close proximity to the royals. She spent seven years as assistant curator of Historic Royal Palaces, responsible for Hampton Court, the Banqueting House in Whitehall and the Tower of London.

She is the author of several historical books on the British monarchy, including The Last Royal Rebel: The Life and Death of James, Duke of Monmouth and The Restless Republic: Britain Without a Crown.

It was reported last weekend that King Charles wanted a female author for the task and the academic was in talks for the role.

Keay, a trustee of the Royal Collection Trust and a member of the Queen Elizabeth Memorial Committee, said: “It is a profound honour to have been asked to write the official biography of Queen Elizabeth II. She was our longest-reigning monarch and an extraordinary woman, whose life spanned a century of great change.”

She added: “I am deeply grateful to his majesty the king for entrusting me with this responsibility and for granting me access to her papers, and will do all I can to do justice to her life and work.”