The photograph was taken in a shoot lasting just a few minutes, and it is understood to have been one of the final frames after the King had finished posing and got immediately back to work.
He is sitting at a 19th-century French mahogany writing desk, in front of the painting Jacob and Leah with their sons, Francesco Zuccarelli 1743, acquired for the Royal Collection by George III.
The red box is placed on a giltwood stool, made by Henry Williams in the mid-18th century.
In the background is a distinctive black and white photograph of the late Queen and Duke of Edinburgh, given to King George VI for Christmas in 1951 by the young couple.
New red boxes of his own are currently being made for the King, with six boxes due to carry his royal cypher.
They will contain papers from government ministers in the UK and the realms, as well as Commonwealth representatives, sent from his private secretary’s office to the King wherever he is around the world in a locked, red despatch box.
Further papers, one tied with a ribbon, are seen next to him.