The death of the Queen has triggered plans codenamed Operation London Bridge as the nation enters a period of national mourning.
Here, Sky News provides a day-by-day account of what is expected to happen over the next 10 days, leading up to the monarch’s funeral.
The date the Queen died at Balmoral would traditionally have been D-Day, or D+0, in the plans.
However the late timing of the announcement of her death – at around 6.30pm on Thursday – has meant plans have been shifted a day to allow the complex arrangements to be put in place.
Follow latest updates following death of Queen
Friday 9 September
King Charles III has returned from Balmoral to London where – despite his grief – he held his first audience with Prime Minister Liz Truss.
Sky’s royal commentator Alastair Bruce said the relationship between the monarch and prime minister “is always very private”.
“It is a function of the continuity of the crown that the relationship is maintained,” he said.
A period of national mourning has officially begun across the country and will continue until the day of the Queen’s funeral, the date of which is yet to be confirmed.
Members of the Royal Family and royal household staff will also observe a period of royal mourning until seven days after the Queen is laid to rest.
On Friday, Charles was expected to meet the Earl Marshal – the Duke of Norfolk – who is in charge of the accession and the Queen’s funeral, to approve the carefully choreographed schedule for the coming days.
The King is addressing the nation on television at 6pm.
A service is being held at St Paul’s Cathedral, with the prime minister and other senior ministers expected to attend and 2,000 seats available for members of the public.
Saturday 10 September
Charles III will be formally proclaimed King at the Accession Council, which meets at 10am at St James’s Palace in London.
Bruce said the Accession Council is a “constitutional necessity”.
“It derives from Saxon times when all the great chiefs of the land would meet and elect from the living descendants of the god King Woden,” he added.
First, the Privy Council – which includes politicians, senior members of the clergy and Supreme Court justices – gathers without the King to proclaim the new monarch and arrange business relating to the proclamation.
Then the King will hold his first Privy Council and will make his personal declaration and oath to “assume the duties and responsibilities of sovereignty” and follow in the footsteps of his mother.
The Queen Consort and the King’s son William, now the Duke of Cornwall, are both members of the Privy Council and are expected to attend.
The first public proclamation of the new sovereign is read in the open air from the Friary Court balcony at St James’s Palace by the Garter King of Arms.
Bruce said this is “the moment technically in the old days people would have found out that the late Queen is dead and that the new King is now sovereign”.
As the proclamation is read out, a 41-gun salute will be fired by The King’s Troop Royal Horse Artillery in Hyde Park.
Union flags go back up to full-mast at 1pm and remain there for 24 hours to coincide with the proclamations before returning to half-mast.
Explaining this tradition, Bruce said: “We must always remember that while we’re sad about the previous monarch dying, we’re delighted to announce that there is a new king.”
The King’s coronation will not take place immediately. The Queen was not crowned for more than a year after her father’s death.
Sunday 11 September
The Queen’s coffin is expected to be taken by road to the Palace of Holyroodhouse in Edinburgh.
The King, who succeeds his mother as head of the Commonwealth, is expected to have an audience with his secretary-general.
Bruce said the head of the Commonwealth is not a title that the King “naturally inherits”.
“It is something the Commonwealth agreed to some years ago, so he is now the new head of the Commonwealth,” he added.
Proclamations will be read in the Scotland, Wales and Northern Ireland devolved parliaments.
Monday 12 September
A procession is expected along Royal Mile in Edinburgh to St Giles’ Cathedral where the public may get the chance to file past the Queen’s coffin at a mini lying in state.
A service will be held in St Giles’ and the Queen’s children are expected to stage a vigil around the Queen’s coffin, known as the Vigil of the Princes.
Contingency plans for the death of the Queen in Scotland were codenamed Operation Unicorn.
Bruce said he expected the Crown of Scotland would be placed on the Queen’s coffin while she lay in state there.
“This is a separate crown to the one she was crowned in,” he said. “It is a symbol of the Scottish nation that is kept in Edinburgh Castle.”
In Westminster, the House of Commons and the House of Lords are expected to come together for a Motion of Condolence, which the King could attend.
After leaving England and visiting Scotland, Charles will at some stage travel to the other countries of the UK – Wales and Northern Ireland – known as Operation Spring Tide.
Tuesday 13 September
The Queen’s coffin is due to be flown to London and is expected to rest at Buckingham Palace in the throne room, where it will be dressed with a crown, orb and sceptre.
A rehearsal for the procession of the coffin to the Palace of Westminster is expected to take place.
Wednesday 14 September
The Queen’s lying in state is expected to begin in Westminster Hall, codenamed Operation Marquee, following a ceremonial procession through London.
It will last four full days.
The Archbishop of Canterbury may conduct a short service following the coffin’s arrival.
Hundreds of thousands of people are expected to file past the coffin on its catafalque and pay their respects, just as they did for the Queen Mother’s lying in state in 2002.
Senior royals are also expected to pay their own moving tribute, standing guard at some stage around the coffin – the tradition known as the Vigil of the Princes.
Thursday 15 September
The Queen’s lying in state continues and a rehearsal is likely to take place for the state funeral procession.
Friday 16 September to Sunday 18 September
The Queen’s lying in state will end on Sunday 18 September. Heads of state are expected to begin arriving in the UK for the funeral.
Monday 19 September
The Queen’s state funeral is expected to take place at Westminster Abbey in central London.
It is thought that there are plans for the Queen’s coffin to process on a gun carriage to the abbey.
The military will be expected to line the streets and also join the procession.
Following the tradition of the funeral of Diana, Princess of Wales, and the Duke of Edinburgh, it is expected that the family will follow behind the coffin.
Heads of state, prime ministers and presidents, European royals and key figures from public life will be invited to gather in the abbey, which can hold a congregation of 2,000.
The service will be televised, and a national two minutes’ silence is expected to be held.
The same day as the funeral, the Queen’s coffin will be taken to St George’s Chapel at Windsor Castle for a televised committal service.
The Queen’s final resting place is thought to be the King George VI memorial chapel, an annex to the main chapel – where her mother and father were buried, along with the ashes of her sister, Princess Margaret.