Britain celebrates Queen Elizabeth II's 90th birthday on Thursday, with her eldest son Prince Charles paying tribute in a special radio broadcast and Prime Minister David Cameron leading a parliamentary homage.
King Charles III and Queen Camilla. Are you ready?
Last week a detailed report revealed exactly what will happen when the Queen dies, the Guardian reported, including the use of a secret code to prevent news leaking out before officials have been notified.
From there a plan will kick off to alert the world that the longest-serving head of state has died.
But when the time comes, is the world ready for Charles to take the throne, and for Camilla to be by his side as Queen?
Contrary to popular opinion, Charles - the world's most patient trainee with the hardest act on the planet to follow - will be king.
Prince Charles and the Duchess of Cornwall are welcomed onto Turangawaewae Marae in Ngaruawahia during their tour to New Zealand. Photo / File
Just as Queen Elizabeth became the new monarch upon the death of her father, King George VI - on February 6, 1952, while she was on tour in Kenya - Charles will be King from the moment the Queen passes away.
Australian Monarchist League succession expert James Ellis told news.com.au that any romantic notion of skipping over Charles to bestow the monarchy on his popular son Prince William was fanciful.
"It's not a popularity contest," Ellis said. "The heir to the throne does not renounce their right to succession.
"Charles will be king."
Ellis said the idea of Charles renouncing his right to the throne may have its roots in the abdication of the Queen's uncle Edward VIII, which left his brother - the Queen's father - to be king.
The event took place in 1936, and was a "constitutional crisis" for the monarchy.
But Ellis said Edward VIII was a "reluctant" vacated of his rightful inheritance and that times had changed since an English king had to abdicate before marrying a twice divorced woman such as Wallis Simpson.
"It was an issue then because the king is also the head of the Church of England," he said.
Prince William and Catherine visited New Zealand in 2014. Photo / File
Majesty Magazine's editor-in-chief Ingrid Seward agreed notions of the crown skipping over Charles to land on William were incorrect.
"Being the heir to the throne is not a job," she said.
"It is a heredity thing and whether you like it or not you are next in line, ie Charles and then William.
"So of course Charles will become King ... unless he dies before his mother."
Four generations of royals - Prince Charles, Queen Elizabeth, Prince George and Prince William. Photo / AP
Inside St James Palace before Britain's Accession Council, Richard Tillbrook, clerk of Britain's Privy Council will read out the proclamation of the new king.
Charles will then introduce his wife as Queen Camilla.
Trumpeters will blow their horns from the palace balcony, ritual proclamations will begin and then King Charles II and Queen Camilla will step out to greet the crowds.
It may not be for another year that Charles' coronation ceremony is held, but Professor Flint said that "sacred" moment will be so unusual and special, it may even captivate cynics.
"It is the last true coronation in the world, a mystical and religious ceremony that survives today," he said.
The Prince of Wales mingles with teachers and students during his visit to Tawa College in Wellington. Photo/ File
"The Archbishop [of Canterbury] is actually crowning the king, anointing him with holy oil. It goes back to the kings of Israel.
"At the Queen's coronation they televised everything else, but there was still a canopy over the Queen, so scared was that moment."
While no-one is ushering out the Queen just yet, understandably there is speculation about what will happen next, especially given a couple of recent bouts of ill health.
This Christmas-New Year season, the Queen's heavy cold meant she missed a series of public engagements and went unseen, sparking rumour she was seriously ill.
Now she is well again, the Queen - even at age 90 - appears robust and the notion of her death comfortably distant.
Queen Elizabeth was unwell over Christmas and New Year and there were fears for her health. Photo / AP
Charles' time as monarch - even if like his parents he lives into his 90s - may at best span 25 years.
"Because of his age when he ascends to the throne - well into his 70s - Charles will be seen as a transitory monarch, compared with the Queen," said Ellis.
"Next in line is William, and then George, and there will be a series of titles bestowed on William and Harry after Charles is king.
"We will see three generations of kings which is what society was used to in the English monarch before Elizabeth II."
Ellis said because Queen Elizabeth had reigned for 60 years people had come to associate the word Queen with the sovereign. Therefore it may be difficult for her subjects to think of Queen Camilla.
And while Camilla will be by her husband's side as he takes the throne she will not have any ruling power.
"She will be Queen consort, with no ruling power whatsoever," said Ellis.
The Prince of Wales and Duchess of Cornwall. Photo / File
The Guardian predicted a "huge and very genuine outpouring of deep emotion" in the wake of the Queen's death to tide over the "awkward facts of succession".
Ellis said people will remember the Queen as "a stabilising force in a rapidly changing world" and may have to adjust to Charles as her successor.
"When you think of the Queen's reign, from just seven years after the end of World War II, there isn't a single global event in recent history she hasn't been witness to," he said.
"She's been an anchoring point and will be missed. But Charles will know what to do.
"It's been the longest apprenticeship and may at first seem like being the warm up act after the main event.
"One of the first things he will do is tour the Commonwealth and I believe he will be well received."
Prince Charles has voiced his views on architecture and global warming. Photo / AP
Australians for Constitutional Monarchy's national convener, Professor David Flint, said Charles "will be the sort of king you want: he will be dignified, he is a man of good will, interest in service and has a good sense of humour"
"There is an opinion poll that says his son is more popular, but I think Charles will be accepted," Professor Flint said.
"People are already warming to him, as interesting a man as he is.
"He may upset some people with his personal opinions about architecture and global warming, but I think he won't continue to express those opinions as king."
Throughout the Commonwealth, opinions rage about the next monarch's capacity to rule.
Prince William and Catherine, the Duchess of Cambridge with their children Prince George and Princess Charlotte. Photo / AP
Is he fit for the job? Is he a doddering old greenie who talks to plants and who married the woman with whom he cheated on poor Diana?
There will also be some reflection on how different it would have been with Queen Diana, even 20 years after her death.
But Ellis said that as time has passed and Charles' image has "mellowed", Camilla has also been accepted, and her genuine work for a list of worthy causes recognised.
Revelations in a new book, Prince Charles: The Passions and Paradoxes of an Improbable Life say Prince Philip bullied Charles into marrying Diana because his true love, Camilla, was not a virgin, as was customary for the bride of the future king.
Prince Charles married Diana in July 1981. Photo / File
She had married Andrew Parker Bowles in 1973, but it has been speculated she rekindled her earlier romance with Prince Charles by the late 1970s.
What later emerged did not endear her to Charles' future subjects, particularly after Diana's tragic death in a 1997 car accident.
Their relationship, which became public after he and Diana divorced, attracted international scrutiny until their 2005 wedding, after which many "forgave" Camilla.
Sam Knight says in London Bridge is down, "Camilla's accession as queen will test how far [her quiet success] ... has come".
But Ellis believes Camilla might be a quiet achiever as consort to her king.
"She's not a Princess Diana or a Kate Middleton, but she has made achievements in her role and there is a warmth about her," he said.
Camilla the Duchess of Cornwall supports many causes including animal welfare. Photo / File
The Duchess has been raising awareness about rape and sexual abuse, talking with victims in the UK and around the world.
A big reader, she is also an advocate for literacy, once saying: "I firmly believe in the importance of igniting a passion for reading in the next generation".
Her other causes include animal welfare, poverty and homelessness.
James Ellis says the early days of the new king will include Prince William inheriting his father's titles such as Duke of Cornwall and Duke of Rothesey.
"Harry will also probably get a dukedom," Ellis said.
"Whether William becomes Prince of Wales is up to Charles, because it is an invested title which has to be bestowed.
"But I would expect that would happen in the first year or two."
The Prince of Wales met head boy Jushua Nightingale, 18, and head girl Briana Boele van Hensbroek, 18, during his visit to Tawa College. Photo / File
King Charles III and Queen Camilla's tour of the Commonwealth within the first year of his reign would help to place their stamp on the sovereignty.
Some countries might use the occasion to usher in a republic, but would those of us down under vote to end the British monarch as head of state?
Professor Flint says support for an Australian republic has declined since the 1999 referendum, and young people were more wary of what he describes as a flawed model of governance.
"Republicans will see it as the moment to strike, but when Charles becomes king, it will happen in the blink of an eye," he said.
"There will be an enormous retrospective over the Queen's reign. That will dominate, and then people will become fascinated with the coronation."
He said the royal family as a whole had grown in appeal for their "sense of service, sense of grace" and that respect would extend to the new king, who might see a bounce in his personal polls.
Ellis was confident the people would warm to Charles.
He said the crowds who come out to greet the couple may not match the throngs who cheered the new Queen and her husband on the 1954 tour of the Commonwealth.
During their 58 days in Australia, the Queen and the Duke of Edinburgh visited 57 cities and towns.
An estimated 75 per cent of the population turned out and the royal tour was the biggest single event organised in Australia before that date.
"People say Charles won't draw those sorts of crowds," Ellis said.
"Again, it's a different era, when people can watch a royal tour on their iPhones rather than be there, but he will be a good monarch."
