READ MORE:
• Inside Harry and Meghan's lavish $27 million LA mansion
• Prince Harry and Meghan Markle's international 'agenda' revealed
• New movie to expose truth about Harry and Meghan's dramatic exit
• Meghan Markle and Prince Harry anniversary: Crushing reality of royal wedding photo
About 30,000 people attend the Queen's garden parties, which she also holds at her official Scottish residence, Holyrood House.
The entire Buckingham Palace garden party routine is organised with military precision. The roughly 8000 people who attend each event are piled in, thoroughly stuffed with cake, then turfed out again in three hours.
They are a staunchly predictable affair, run to a timetable, with the only wildcard being which of the younger HRHs would be dragooned into joining Her Majesty and what particularly violent shade of neon the 94-year-old would be wearing.
It was at just such a garden party in 2018 that Meghan Markle made royal history: only three days earlier she had wed Prince Harry.
This was her first official event as a member of the royal family and the first chance for a gawping, enthralled public to see how she would fare in her new job of duchessing.
Looking at photos of the event tugs at the heartstrings a tad. A beaming Meghan resplendent in a pink dress by British label GOAT, laughing and joking with Prince Charles and Camilla, Duchess of Cornwall. Here was the thrilling future of the royal family: inclusive, loving and deliciously glamorous.
One shot stands out: it is taken from a distance and it is clearly an unguarded, personal moment. Camilla and Meghan are deep in discussion, holding each other's hand.
There is a tenderness and intimacy here that is wildly out of the usual regal realm.
At first glance, Meghan and Camilla have very little in common. The former fell for her royal charmer and they wed after a whirlwind romance; the latter endured a tumultuous, at times adulterous, liaison that stretched out for several long, emotionally wrought decades.
Meghan had thoroughly made a mark as a professional woman and entrepreneur before she married; Camilla had - pre her matrimonial years - worked for society interior designers Colefax & Fowler.
However, look closer and there are interesting parallels between the two women.
Even 20 years ago, the prospect of either of them marrying into the British royal family was nearly non-existent.
Both are women who, when they became duchesses, faced elements of stiff public opposition to their having been welcomed into this rarefied social milieu and family, and both have at times been vilified by sections of the media.
On the flip side, both are not afraid of hard work and have brought untold joy and love into the lives of two Princes who had struggled to find personal happiness.
Which is why seeing Meghan and Camilla during that moment in 2018 represented such an opportunity for two intelligent royal recruits to take matters into their own hands and do things differently.
Looking back at royal events of the past 40-odd years, pretty much all of the greatest dramas and controversies have stemmed from the travails and struggles of ordinary women who have married into the royal family, only for them to be seemingly left to learn the surreal, antiquated ropes of this business by themselves.
There is no training course or clearly laid out instruction manual with diagrams on how to become royal.
This is a profession you can only pick up on the job, and for many new recruits, their on-the-job apprenticeship is a tumultuous, painful experience.
Think Diana, Fergie and Sophie Wessex: all three were largely thrown in the royal deep end, and some learned to swim far better than others.
Kate Middleton, by contrast was given nine years to truly understand what she was getting herself into before marrying William and then had a couple of years of part-time royal duties to ease her into things.
Consider what it really means to be a duchess or a princess: exchanging the only life you have known for complete and utter immersion in an alien universe governed by umpteen rules and regulations, from who can enter a room first to how to close a car door.
Which is why Camilla and Meghan could have been such a powerful duo.
I'm not suggesting that if Meghan and Camilla had formed a two-woman HRH support group the course of recent royal history would be dramatically different.
For all we know, Camilla might have reached out to Meghan and invited her round to Clarence House for a triple G&T and a confab to help her learn the ropes, or Meghan might have suggested that Camilla join her for a crystal healing session and a heart-to-heart about Windsor do's and don'ts.
But imagine if Meghan had been given, by Camilla or anyone else in possession of a tiara, a title and years of curtsying experience, the sort of tutelage any woman would need when thrust into this strange new world and its swathe of arcane, obscure codes of behaviour.
Surely that would have made navigating the byways and intricacies of royal life just that much less arduous and stressful, and would have made Meghan's transition into palace life that much easier.
Beyond the practical, this would have represented the sort of emotional support that Meghan evidently felt was lacking.
In October last year, when ITV's Tom Bradby asked her how she was coping, she replied "Thank you for asking because not many people have asked if I'm okay".
"But it's a very real thing to be going through behind the scenes."
The impression is that Meghan, despite being surrounded by staff and servants, felt somewhat alone in this new world. I wonder how much difference having an ally on hand, one who had trod a similar path to her, might have made in terms of helping her acclimatise to being the newest Windsor might have made.
This year, the Buckingham Palace garden parties have been cancelled and the Queen is at Windsor Castle with no plans for her to return to London anytime soon.
And Harry and Meghan, as we all know, are in Los Angeles, embarking on a new life in a city where she intimately knows the ropes.
In 2018, she made the wild leap from civilian life to royalty and today, it's Harry's turn to make that return journey, from HRH-dom to normalcy.
Let's hope that history does not repeat itself.