It was the moment the Queen realised all was not well with her grandson and his American wife.
Having still not heard whether Prince Harry, Meghan and Archie would be spending Christmas at Sandringham, the 94-year-old monarch broke with tradition and decided to personally telephone the couple at Frogmore Cottage last November.
Ordinarily it is for the younger royals to phone "Granny", and not the other way round, but having heard tales of tantrums and tiaras ever since the Sussexes married at Windsor Castle in May 2018, HM resolved to seek answers straight from the horse's mouth.
Suffice to say the sovereign was more than a little surprised to learn, several days later, that they were not only planning to spend her great-grandson's first Christmas elsewhere, but on a six-week sabbatical to Canada to "work out their future".
Holed up in a multimillion-dollar mansion on Vancouver Island, the couple "secretly plotted" their decision to exit the Royal Family with the help of a small group of friends and advisers in North America, including Meghan's Sunshine Sachs PR supremo Keleigh Thomas Morgan, attorney Rick Genow, business manager Andrew Meyer and talent agent Nick Collins.
It came after they secretly registered their royal website, sussexroyal.com, in March last year, amid reports of rising tensions not only with the Duke and Duchess of Cambridge - but aides to both the Queen and Prince Charles.
Insiders say they first began raising the issue of a retreat from royal life around the time of their first wedding anniversary a few months later, when they filed to trademark "Sussex Royal" with the Intellectual Property Office (IPO), to cover a range of "goods and services", including items such as magazines, calendars, posters, greeting cards and clothing.
So when matters finally came to a head on their return to the UK on Monday, January 6, it is true to say the royals already knew trouble was brewing. Indeed, aides had been summoned to Frogmore that night and informed of their decision - and spent the next 24 hours "trying their damndest" to persuade them to hold fire, fearing they would be "shooting themselves in the foot".
As their friend Tom Bradby, the ITV news anchor, later confirmed, Harry lobbied to meet with both the Queen and Charles to discuss their plans to work towards becoming financially independent in a newly slimmed-down monarchy - only to be rebuffed by officials who insisted he put pen to paper with some ideas for discussion.
His reluctance, on the grounds that such documents normally leak, laid bare the inherent mistrust at the heart of Harry's relationship with Clarence House, his father's household, which he felt had always been too keen on column inches to understand his moral stance against the media.
Harry and Meghan were then understandably left furious when details of their plans appeared on the front of The Sun newspaper on the morning of January 8, declaring the couple were "orf" to Canada.
As extracts from a new biography of the couple, published on Saturday, are expected to reveal - Harry's anger predominantly lay with what his mother famously described as the palace's "men in grey suits" - rather than his own royal relatives.
"He would get so frustrated when he was told he couldn't do something," revealed one insider. "The palace approach would always be - how did we do it last time? He wanted to do things differently and I think Meghan was the catalyst for him but also gave him the confidence which he lacked to change things."
As Finding Freedom, the book by Omid Scobie and Carolyn Durand, is set to lay bare, the Royal Family had plenty of notice of the couple's intentions - even though the Queen was genuinely "blindsided" when Harry and Meghan pushed the nuclear button at 6.30pm on the evening of January 8 by releasing their bombshell statement on Instagram.
As one insider put it: "Harry felt very constrained. He wanted to be able to speak to his grandmother and his father but constantly found aides blocking his path. It was so frustrating for him. Some people think the Sussexes leaked the story to the Sun to bounce the Royal Family into something - almost out of desperation - but I'm not sure that's true."
The swiftness with which Buckingham Palace responded to the statement, issuing a terse reaction at 8.13pm saying: "these are complicated issues that will take time to work through," took the couple somewhat by surprise, following what they perceived as weeks of unwillingness to engage.
The Queen, meanwhile, was said to be "disappointed and hurt" by the couple's "suboptimal" behaviour.
Determined for the situation - and accompanying press coverage - not to be dragged out, it was Her Majesty who insisted that aides should come up with a solution within 72 hours.
Having insisted the crisis should last no longer than the six days that elapsed between Prince Andrew's car crash Newsnight interview and his stepping back from royal duties - the Sandringham summit was promptly scheduled for the following Monday, January 13.
Arriving on the 20,000 acre estate in Norfolk two hours early, Harry immediately sought out his grandmother in her private apartments on the first floor and the pair spent more than an hour alone together before being joined by Charles and William, who arrived just 15 minutes before the 2pm meeting. Prince Philip was conspicuous by his absence.
According to one well-placed source: "The most important thing the summit achieved was putting the brothers back in the same room. They were finally back on speaking terms."
Seeds of tension
It is no secret that "really damaging things were said and done" in the run-up to the Sussexes' wedding but tensions undoubtedly first surfaced when a concerned William took his occasionally impetuous brother aside around the time of the engagement in November 2017 and said: "Are you sure about this?"
Insiders have also suggested that the Cambridges "did not make Meghan feel particularly welcome" when she first moved to Britain - although sources close to the couple have stressed that they were simply looking out for Harry's best interests.
"You have to remember that Kate and Harry were always very close too," one insider said.
Even before he met Meghan in the spring of 2016, Harry was growing increasingly frustrated by being in William and Kate's shadow.
"It wasn't a rivalry between the brothers but more a sense that they would be competing over who would lead on their various issues," said one source.
"Harry felt awkward as a plus one. They'd turn up at premieres and there was this sense that he felt a bit like a spare part.
"Long before Meghan, he wanted to change things. He wanted to control his own narrative. He would say, 'Why can't we use social media or record videos and cut out the press?"
Although the Sussexes certainly felt "pushed out" by the Cambridges' supremacy in the Royal pecking order - their vastly different approaches to the media also drove a wedge - not only between the couples but also their shared staff at Kensington Palace.
While William and Kate were happy adopting the palace's "never complain, never explain mantra", the Sussexes seemingly wanted to react to practically every negative headline - much to the chagrin of their closest advisers.
According to one former aide: "They wanted to change things and do things differently, but it went wrong when it became us against the rest of the world. They didn't seem to understand that they had started spinning a negative message. The attack on the press, the preaching while taking private jets, it was all so self-damaging."
Palace aides sidelined
With Meghan still in constant contact with her US entourage, palace staff including their former private secretary Samantha Cohen and their former communications secretary Sara Latham soon started feeling frozen out.
"They realised the couple weren't going to take their advice," the aide said.
A string of staff departed under the pressure including assistant private secretary Amy Pickerill and Meghan's PA Melissa Touabti.
According to one source: "Meghan is clearly someone who knows what she wants and is very self assured. But that made her very difficult to work for. At times she could show extraordinary kindness and be very sweet but at others she was very self-centred and lacking in any self awareness.
"She would say: 'Why do we have to do this?' or simply: 'I'm not doing this'. She didn't understand that there were not just jobs she had to do but that she should do.
"She was behaving like a celebrity in firing off early morning emails and making huge demands of staff."
Another insider revealed how aides resented the fact that by returning to Canada before the Sandringham summit, the Duchess largely left Harry to "face the music" - although the couple did bid a final farewell on March 12.
That staff were always so fiercely loyal to Harry - as one of the most popular 'principals' behind palace gates - may also have posed problems for Meghan, as an outsider. "There were employees who worked for Harry expressing relief that they weren't working for her," added a source.
Hence the row over Meghan's wedding tiara - during which Harry is alleged to have told one of the Queen's closest aides, thought to be her dresser Angela Kelly: "What Meghan wants Meghan gets," prompting fury "below stairs".
Staff appeared to turn their nose up at the idea of kowtowing to the demands of "an actress on a cable show" when they had "signed up to serve Queen and country". News that Meghan had made Kate cry during a bridesmaid's dress fitting for Princess Charlotte hardly endeared her to Cambridge loyalists either.
Advisers were already put out that the Sussexes were increasingly operating in a silo - refusing to give Buckingham Palace advance notice that Meghan was in labour, and deciding Archie's christening date before informing the Queen, which consequently meant she couldn't make it.
"There was certainly this growing unease among staff, thinking - they are acting as if they are bigger than this institution, who the hell do they think they are?" the source said.
As far as Harry and Meghan are concerned, however, the stuffy, outdated and ultimately "discriminatory" palace missed out on a golden opportunity to change for the better, supported by prejudiced media armed with a vendetta against them.
Yet while Finding Freedom may accuse both courtiers and the press of being motivated by racism - anti-Americanism, combined with a refusal to see the monarchy overhauled on the whim of the sixth-in-line to the throne, may emerge as a more accurate description.