The King is to have a private day of reflection after a momentous period that saw him become monarch.
Charles has returned to his Highgrove home in Gloucestershire and is not expected to attend any public events on Thursday.
In the detailed planning for the aftermath of the Queen’s death – known as “London Bridge” – a day was set aside at this point for the new monarch to have some time away from public duties.
The period will allow the King to pause, but it is understood he will be working in preparation for his new role and will already be receiving his red boxes of state papers.
The new monarch led the royal family in a public display of homage to the late Queen by walking behind her coffin with his siblings, sons and other relatives as it was carried into Westminster Hall, where it will lie in state until the state funeral on Monday.
Watched by tens of thousands lining the route from Buckingham Palace, the King delivered his mother to the hands of the nation for a period of four days.
Every day of the year, except Christmas Day, he will receive from government ministers – and from representatives in Commonwealth and foreign countries – information in the form of policy papers, cabinet documents and Foreign Office telegrams.
The correspondence also includes a daily summary of events in Parliament, letters and other state papers which are sent by his private secretary in the red boxes also used by Government ministers to carry confidential documents.
All of the papers have to be read and, where necessary, approved and signed.
The red boxes are made by leather goods company Barrow and Gale but it is not known if Charles has received a new set or is using the Queen’s boxes for the time being.
The late Queen still used the boxes that were made for her on her coronation in 1953, having had them refurbished over the years.