In the 1980s, it was the question of apartheid-era South Africa that threatened to drive a wedge through the Commonwealth.

But while some credit the Queen then with a heroic role behind the scenes – dramatised with more than a dollop of artistic licence in season four of The Crown – in 2021 the threat comes from a row over alleged racism within the royal family itself.

Recollections by the Duke and Duchess of Sussex of a royal figure commenting on “how dark” their future son’s skin could be are being “weaponised” in looming debates in member states about becoming republics, it is suggested, as senior former Commonwealth diplomats or government figures also warn it would deepen schisms.

They include Jamaica – where opposition MPs continue to press for a referendum on removing the Queen as head of state.

And in a little-noticed announcement this week, the UK government appointed Britain’s high commissioner to Barbados, which has said it intends to become a republic by November 2021.

Scott Furssedonn-Wood takes up the potentially delicate role after – coincidentally – spending the past four years as deputy private secretary to Prince Charles.

“In debates in the Caribbean, an area which has a lot of Commonwealth roles, [the Meghan and Harry interview] is going to have an impact and is the kind of issue that could be weaponised in support of a republic,” said Philip Murphy, the director of the University of London’s institute of Commonwealth studies. He pointed out that it would be Charles representing the UK in June at the Commonwealth heads of government meeting, already overshadowed by its Rwandan host’s human rights record.

Guy Hewitt, a former Barbadian high commissioner to the UK, told BBC Newsnight that the decision of Barbados to become a republic reflected what the current discussion had captured.

“The inconsistency between an institution and monarchy which reflects an oppressive and racist colonial past and where countries want and aspire to be in the future,” said Hewitt, who contrasted the silence of the Queen on the Windrush scandal with how she had “spoken out” against Scottish independence.

As for the revelations from the Oprah Winfrey interview, he said: “I would say it underscores and affirms that Barbados did make the right decision to have a native born citizen as head of state. It speaks to social media. Young people are responding and really putting support behind Harry and Meghan because any outcry, especially by a black woman, must be given credibility and support.”

Peter Wickham, a Barbadian political analyst, said: “The recent crisis has indeed highlighted attitudes within the royal family that many of us would find offensive and does help to foment the anti-royal sentiment.

“There are many among us who consider this sentiment to be a reflection of the broader British society and the Brexit discussions, which reveal a British preoccupation with their ‘specialness’ does not help.”

That said, he added that the issue of any Commonwealth member becoming a republic was not as simple as it might appear. While Barbados had the option of becoming a republic “at the stroke of a pen”, he recalled that referendums had failed recently in Antigua, Grenada (twice) and St Vincent.

Even beyond the Caribbean, where the legacy of the Windrush scandal has also weighed heavily on the relationship with the UK, the claims from Meghan and Harry’s interview with Winfrey have been causing consternation.

After the broadcast, the former Australian prime minister Malcolm Turnbull cited it as another reason for the country to sever its constitutional ties to the British monarchy.

“After the end of the Queen’s reign, that is the time for us to say: ‘OK, we’ve passed that watershed,’” Turnbull told the Australian Broadcasting Corporation.

“Do we really want to have whoever happens to be the head of state, the king or queen of the UK, automatically [as] our head of state?”

Harry and Meghan have been among the new generation of royals used to further British “soft power” and were deployed in the past to Commonwealth-related events with young people, businesses and volunteer groups.

But their Oprah Winfrey interview “opens our eyes further” on the merits or not of the Commonwealth, wrote Nicholas Sengoba, a newspaper columnist in the former colony of Uganda.

He cited “unresolved issues” in his country relating to the abuses of colonialism and questioned whether the heads of Commonwealth countries should still be “proud to eat dinner” with members of the British royal family, considering the accusations.

Just days ago the Queen delivered a message of unity to the Commonwealth, telling members: “We have an opportunity reflect on a time like no other.”

But while her message emphasised, as ever, the ties that bind the 90-year-old association, the interview in Los Angeles depicted the royal institution she heads in a very different light.

After telling Winfrey about the conversation regarding Archie’s skin colour, Meghan added: “The Commonwealth is a huge part of the monarchy, and I lived in Canada, which is a Commonwealth country, for seven years. But it wasn’t until Harry and I were together that we started to travel through the Commonwealth, I would say 60% , 70% of which is people of colour, right?”