The Queen's coffin is to begin its poignant final journey to Buckingham Palace, while the King will travel to Northern Ireland for the first time as monarch.
Thousands of members of the public moved solemnly past the oak coffin throughout the night on Monday as it stood on public view for 24 hours at St Giles' Cathedral in Edinburgh.
Charles, on his Operation Spring Tide tour around the UK with the Queen Consort, will leave Scotland and head to Belfast before returning to London in the evening.
Members of the public are already queuing for the Queen's lying in state at Westminster Hall, which opens on Wednesday, with thousands placing floral tributes in London's Green Park.
Mourners have been asked by Royal Parks not leave marmalade sandwiches - a nod to the Queen's popular comedy sketch with Paddington Bear - for fear of a negative effect on wildlife.
At 6pm on Tuesday (3am Wednesday AEST), the Queen will depart Scotland for the final time.
Her coffin will be flown from Edinburgh Airport to London on an RAF Globemaster C-17 flight, accompanied by her daughter the Princess Royal.
The King will be joined by Camilla as he receives his mother's coffin at Buckingham Palace, where she spent so many of her decades as sovereign.
The Prince and Princess of Wales will also be at the Palace.
A guard of honour formed of three officers and 96 soldiers from The King's Guard will be mounted in the Quadrangle.
Military commands, usually shouted, will be given as quietly as possible in honour of the solemn occasion.
The coffin will be carried by a bearer party to the Bow Room where a sovereign's piper will play a lament.
It will remain in the Bow Room overnight before a procession on Wednesday to Westminster Hall for the start of the lying in state.
The King's visit to Northern Ireland earlier in the day comes ahead of a trip to Wales later in the week.
After touching down in Belfast, Charles and Camilla will travel to Hillsborough Castle in Co Down, the royal residence in Northern Ireland, for several engagements.
They will hold a private audience with the new Northern Ireland Secretary Chris Heaton-Harris, as well as meeting representatives of political parties in the region.
The couple will receive a message of condolence on behalf of the people of Northern Ireland.
Charles and Camilla will then travel to St Anne's Cathedral in Belfast where they will attend a service of reflection for the life of the Queen.
The new monarch will also meet leaders from all the major faiths in Northern Ireland.
Irish President Michael D Higgins and his wife Sabina, Taoiseach Micheal Martin and Foreign Affairs Minister Simon Coveney are due to attend a memorial service at St Anne's Cathedral.
Both Houses of Parliament gathered at Westminster Hall in London on Monday to express their condolences to the new monarch, and Charles promised "faithfully to follow" the example set by his mother.
Later, the King led the royal family in a procession behind the Queen's coffin in Edinburgh as it was taken from the Palace of Holyroodhouse to St Giles' Cathedral.
© RAW 2022