Prince Charles, Prince of Wales and Prince Harry attend the opening ceremony for the Invictus Games at Queen Elizabeth Olympic Park on September 10, 2014, in London. Photo / Getty Images
The Duke's remarks about the "CBE scandal" will only stress the pair's fractured relationship further, says Camilla Tominey.
It didn't always use to be this way. Before Prince Harry's decision to repeatedly throw his father under a bus, he was arguably closer than Prince William to Prince Charles.
Yet the already fragile relationship between the heir to the throne and his youngest son now appears at breaking point after an increasingly isolated Harry claimed he had raised concerns about the donor in the "cash for access" crisis that has engulfed Charles's household.
Insisting he had "severed ties" with Mahfouz Marei Mubarak bin Mahfouz a year before his father presented the controversial Saudi billionaire with a CBE, the Duke of Sussex has risked another public rift with the royals at a time when most other families are busy planning their end-of-year get-togethers.
In suggesting he had "concerns" over the businessman's motives after he gave tens of thousands of pounds to Harry's charities, the Duke of Sussex pointedly referred to the saga as the "CBE scandal". So much for blood being thicker than water.
They say absence makes the heart grow fonder but, as he continues his Californian lifestyle, living in a Montecito mansion where he counts Oprah Winfrey and Orlando Bloom among his neighbours, Harry could not seem more estranged from the House of Windsor. An ocean away from his brother and London circle, he's raising his two children, Archie, 2, and 6-month-old Lilibet largely without input from his own family. Charles has yet to meet Lilibet, who was born in Santa Barbara and hasn't been to the UK.
Already it hasn't been a good few months for the future king. Charles has been engulfed by criticism over his relationship with Mahfouz and the hundreds of thousands donated to pet projects via his charitable trust.
The prince's senior aide, Michael Fawcett - the man he always said he could not live without - was forced to resign as the head of the Prince's Foundation last month. An independent investigation last week found Fawcett had colluded with "fixers" representing Mahfouz who were trying to secure an honour in return for donations.
Mahfouz is thought to have donated at least £1.5 million to royal charities - including £50,000 to Harry's Sentebale charity and a further £10,000 to Walking With the Wounded, another charity of which he is patron.
Notwithstanding the questions raised by Harry's claim that he flagged concerns about Mahfouz, his latest intervention plants yet another bomb under "the Firm", and has sparked counter-claims from sources that "no one can remember that here".
Coming after the Oprah Winfrey interview, when Harry accused his father and brother of being "trapped" in the monarchy, and complained that Charles stopped returning his calls in the days leading up to Megxit, before "literally" cutting him off financially, his latest claims threaten to further drive a wedge between the Montecito Two and the monarchy.
It is an understatement to say the relationship between Charles and his sons has been complex over the years.
As someone who worked for the family when William and Harry were little explained: "William and Diana had a particularly close connection. Harry was very young for his age. Charles was largely absent and undemonstrative but unmistakably affectionate."
Referring to the Princess of Wales's now discredited 1995 interview with Martin Bashir, the source added: "I think the dynamics changed quite a lot after Panorama."
Although Diana's death undoubtedly brought all three princes closer together, of the two brothers it was always Harry who appeared the more understanding of their father's laissez-faire, workaholic approach. Although he made mistakes as a teenager, there is a sense that Charles found it difficult to admonish "loveable" Harry, while his relationship with William, who witnessed much more of his mother's marital distress than his younger brother, was thought to be more of a challenge.
During the events to mark the 20th anniversary of Diana's death in 2017, it was Harry who said: "He was there for us, he was the one out of two left and he tried to do his best and to make sure we were protected and looked after."
Amid reports that Charles had felt sidelined by the Duchess of Cambridge's parents, Michael and Carole Middleton, when it came to spending time with his grandchildren, relations between father and eldest son were reportedly strained when an unseen photograph of Prince George inadvertently appeared in a video broadcast featuring his grandfather.
At that time, Charles was close to Harry, and was fond of Meghan, too, agreeing to walk her down the aisle at the pair's 2018 royal wedding in her father's absence. But mounting tension between the Sussex and the Cambridge households after the celebration left Charles having to play peacemaker.
The more William and Charles worked together to protect the monarchy from the growing crisis, the more Harry and Meghan are said to have felt marginalised.
With talk of transition in the run-up to Megxit, Charles increasingly involved William in his decision-making - much to the annoyance of Harry, who perhaps felt pushed out by their away days to Duchy of Cornwall estates. While Diana had insisted they be brought up as equals, resentment may have crept in against William for how he appeared to be positioning himself as an exemplar.
The New Year 2020 release of a photograph showing the Queen and her three heirs, Charles, William and George, only served to compound the Sussexes' sense of frustration,
By then Harry and Meghan had already decided they wanted to step down as senior royals - but their mistrust of Charles's operation was laid bare when Harry felt compelled to telephone the Queen about their growing unhappiness, after being repeatedly rebuffed by his father's private secretary, Clive Alderton.
His father had asked him to commit his plans for a "quasi-royal" role to paper, but Harry refused, fearing they would be leaked by Clarence House - hardly a ringing endorsement of his father's operation.
Harry then claimed the Queen's private secretary, Sir Edward Young, cancelled a meeting with her at Sandringham, prompting him to "take matters into his own hands" by issuing their Instagram statement announcing they were stepping back as "senior" royals. Aides insist they are there to protect the royals, but, as one former adviser puts it: "The lines have become blurred. Private family matters used to be completely sacrosanct but lately private secretaries seem to have been overstepping the mark when it comes to trying to manage the royals' relationships with each other."
Money also played a part in the breakdown of the relationship between father and son - as evidenced by Harry's dismay at the plug being pulled on his family's taxpayer-funded security.
According to one well-placed source: "Like any parent, Charles did get fed up with the constant calls from Harry for more money. He ... did his utmost to make them feel financially supported... I think a lot of parents will be able to identify with that."
Parents might also be able to identify with the notion of being hurt by the very people they love the most in the world. It has not gone unnoticed behind palace gates that Harry cutting himself off appears to echo Meghan's relationship with her own father, Thomas Markle.
Tellingly, however, those who know Charles best insist he won't be angry at Harry's latest salvo - just sad. As one former aide explains: "The prince absolutely adores Harry. He will feel absolutely devastated by this - distraught. He'll be beside himself if this means he also becomes more ostracised from his grandchildren."
In the year Charles said goodbye to his beloved father, it looks horribly like he is also in danger of losing his darling boy, too.
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