We will never truly know if the late 'People's Princess' had the mettle to rule, but one thing is for certain - Diana would have been an extremely popular choice in Britain and the Commonwealth.
Sadly, her strong will meant she'd never meet the firm's expectations, leading her to famously declare: "I'd like to be a queen of people's hearts...but I don't see myself being queen of this country."
Camilla, of course, became the "third person" in Charles' doomed marriage to Diana.
When the lovers were finally free to take their romance public, so too began an extensive PR campaign to rehabilitate Camilla's reputation - and boy did it need repairing.
Having dissolved her own union and that of the future monarch, the divorced mother of two was viewed as a royal homewrecker; a persona non grata.
"It has not been easy for Camilla, but she has stuck at it," shares Phil.
As if having Diana's legacy looming over her head wasn't enough to contend with, Camilla has also dealt with the fact that her husband doesn't consider her the woman who knows him best.
Instead, Charles awarded that honour to an Australian baroness: Dale Tryson.
The Melbourne-born socialite and former Australian Women's Weekly reporter was famously nicknamed 'Kanga' by Charles.
They met briefly in Victoria in 1966 but it was via her husband, 3rd Baron Tryon, that Kanga properly entered Charles' inner circle.
She too become the royal's mistress, and he reportedly once declared she was "the only woman who ever understood me."
Eventually, Charles and Camilla married in 2005.
However, given their scandalous history, it was announced at the time that she would be known as Princess Consort when Charles ascended the throne.
This decision was change in February 2022, when the late Queen Elizabeth II marked the 70th anniversary of her reign with her wish for Camilla to become Queen Consort.
"The Queen realised Charles could only reign successfully if he was happy and that's why she came round to Camilla," explains Phil.
"She was content to stay in the background and support Charles, but he was the one who insisted Camilla become his wife and eventually his Queen."