King Charles will be formally proclaimed monarch at a historic Accession Council within hours.

The eldest son of Queen Elizabeth II, Charles has spent his entire life preparing for this moment in the history of the British monarchy.

He automatically became King on the death of his mother, aged 96, at Balmoral Castle on Thursday (UK time). But the formal process takes longer.

When will the formal process happen?

An Accession Council is usually convened at St James’s Palace in London within 24 hours of the death of a sovereign. It will be later following the death of the Queen because the timing of the announcement of her death meant there was not enough time to set the plans in motion for Friday morning.

It is expected to meet on Saturday (Australian time).

It was all part of Operation London Bridge, as preparations for the Queen’s funeral are codenamed. They began immediately upon her death.

“Once London Bridge is down, the Queen’s private secretary [Sir Edward Young] (was) responsible for informing the Prime Minister before the information is released to the 15 other countries where the Queen is head of state and the rest of the 36 Commonwealth nations.

“This is done by the Foreign Office’s Global Response Centre which is housed at an unknown location in London,” britishheritage.com said.

The arrangements are more complex due to the Queen’s death in Scotland. That has triggered Operation Unicorn, the contingency plans in case of such an event.

Operation Unicorn

Across Britain, sporting fixtures scheduled for Friday were largely cancelled, including matches in the English Football League and Northern Ireland Football League. Racing was postponed and play was cancelled in the PGA championship.

The Tour of Britain cycling race cancelled Friday’s racing, while the second day of the Test cricket match between England and South Africa was postponed.

The BBC Proms on Thursday and Friday have been cancelled, along with the Last Night of the Proms on Saturday.

Theatre performances were expected to continue, after observing a minute’s silence.

Elsewhere, the Rail, Maritime and Transport union cancelled strikes planned for September 15 and 17 as a mark of respect. The Transport Salaried Staffs Association has also called off planned strikes in September, while the Communication Workers Union abandoned a planned strike for Friday.

As tributes flowed for the world’s longest serving monarch, with Union Jacks flying at half-mast in Britain and around the world, the official business of Charles’ elevation to monarch began.

Dr Giselle Bastin, associate professor of English specialising in research on royalism and the history of the British monarchy at Flinders University, told The New Daily an Accession Council would be convened at St James’s Palace in London.

“Charles becomes King as soon as his mother dies,” Dr Bastin said.

Charles will take the Oath of Accession inside the palace. It will include a promise to “maintain and preserve the Protestant Religion and Presbyterian Church Government”.

“The new sovereign will not be the supreme governor of the Church of Scotland, as he will be of the Church of England,” Dr Bastin said.

Historically, the entire Privy Council is summoned to the Accession Council to oversee the formal proclamation of a new monarch.

But with the number of privy counsellors – who are lifetime members and mostly past and present politicians – now at more than 700, there are restrictions.

Just 200 will be summoned. Those cut will be asked to enter an annual ballot for a few remaining seats.

Accession Council

The Accession Council must take place before the British parliament meets, and parliament should meet as soon as practicable after the death of a sovereign.

Dr Bastin said “very soon” the British parliament “will be called and peers in the upper house/House of Lords will take an oath of allegiance to the new monarch”.

“The members of parliament in the lower house do not have to,” she said.

By contrast, Australia’s parliament has been suspended for a fortnight. And, in Victoria, all MPs will have to swear an oath of allegiance to the new King before state parliament can resume.

The Accession Council is presided over by the Lord President of the Council, Penny Morduant.

The chosen Privy counsellors will gather at St James’s Palace to proclaim the new sovereign, joined by Great Officers of State, the Lord Mayor and City Civic party, Realm High Commissioners and some senior civil servants.

Charles will not be there. But his wife Camilla – the new Queen – and eldest son Prince William, now known as the Duke of Cornwall and Cambridge, will be present.

“[Camilla] is, also, likely to be crowned alongside Charles and she will become Queen Camilla (she will be a Queen Consort rather than Queen Regnant),” Dr Bastin said.

“She will, I imagine, assist her husband in planning for the coronation.”

Crowds line Pall Mall to watch the Queen on her way to her coronation at Westminster Abbey in 1953. Photo: Getty

Charles’ full title and the first regal roles

When the meeting begins, the Lord President announces the death of the sovereign and calls upon the Clerk of the Council to read aloud the text of the Accession Proclamation.

It will include Charles’s chosen title as King. He has already announced he will be known as King Charles III.

The Queen’s full title was Elizabeth the Second, by the Grace of God, of the United Kingdom of Great Britain and Northern Ireland, and of Her other Realms and Territories Queen, Head of the Commonwealth, Defender of the Faith.

“Charles’s title will have the same components, although he indicated in the early 1990s that he might style himself ‘Defender of Faith’ rather than ‘Defender of the Faith’ in order to recognise the many different faiths in the UK, not just the Church of England,” Dr Bastin said.

The platform party – made up of Camilla and William, the Archbishop of Canterbury, the Lord Chancellor, the Archbishop of York, the Prime Minister, the Lord Privy Seal, the Lord Great Chamberlain, the Earl Marshal and the Lord President – then sign the proclamation.

Charles then enters and holds his first council, which is attended only by privy counsellors.

After the Accession Council, the first public proclamation of the new sovereign is read in the open air from the Friary Court balcony by the Garter King of Arms at St James’s Palace.

Amid great ceremony, trumpeters usually play a fanfare from the balcony and gun salutes are fired in Hyde Park and at the Tower of London at the same time.

The proclamation will then be read at the Royal Exchange in the City of London and in other cities including Edinburgh, Cardiff and Belfast and usually at Windsor and in York.

It is not yet known when King Charles’ formal coronation will be held. But it is likely to be months away.

“Some new sovereigns have been crowned quite soon after the death of their parent/or the former sovereign, but Queen Elizabeth II, for example, became queen on the death of her father in February 1952, but wasn’t crowned until June 1953,” Dr Bastin said.

“The delay could have been because of the size and scale of the coronation and the need for lots of preparation time. King George VI died relatively ‘unexpectedly’, so the coronation organisers may have been caught off their feet a bit.”

Elizabeth II and Prince Philip on the Buckingham Palace balcony after her coronation on June 2, 1953. Photo: Getty

What happens next

Britain has begun 10 days of official mourning for the Queen, a period that will be replicated around the world.

In Australia, there is no official mourning period, though there is likely to be a national memorial service in coming weeks.

Prime Minister Anthony Albanese will declare a national day of mourning, coinciding with the service. One minute’s silence will be observed at 11am.

Flags will fly at half-mast on Commonwealth buildings until the Queen’s funeral, which is expected to be held on September 19.

Before that, members of the royal family are expected to hold a vigil around the Queen’s coffin in St Giles’ Cathedral in Edinburgh in coming days. After that, her Queen’s coffin will be transported in a Royal Air Force plane back to London.

She is expected to lie in state in London for several days, with her funeral to be held at Westminster Abbey.

-with AAP