British King Charles III, who is the also head of state in 14 overseas realms, have been issued new warnings amid growing anti-monarchy protests.
The 74-year-old, who's set to be crowned alongside his wife Camilla in May, will likely be the last British monarch in some of the overseas realms still considering him their head of state, a historian believes.
Andrew Walkling, Professor at Binghamton University in New York, believes this is "inevitable", adding having a British monarch leading countries overseas is increasingly being perceived by many as a "relic of a past notion".
It comes as republican sentiment is on the rise in Australia, which has recently decided to ditch the King from its banknotes.
Asked whether King Charles is facing a wave of republicanism in the overseas realms, Professor Walking told Express UK: "It does actually seem to me as though there is a growing desire to eliminate the monarchy in overseas territories and that includes both larger countries like Australia and also very small nations like some of the Caribbean ones.
The Professor added: "That is all about the legacy of colonialism. Their connection to Britain was rooted in the imperial project abroad. I think a lot of people are starting to think, 'this is a relic of our past time and a past way of thinking about things and we need to move on'."
He said the decision to become republics would signal these countries are "imagining a new future for themselves" rather than a desire to stop having a relationship with Britain as they still want to hold on to and treasure.
The expert continued: "Many people would argue that the legacy of colonialism needs to be set aside and therefore to have Charles III as King of Papua New Guinea is a bizarre concept. In that respect, I think it's likely that that will continue to develop in that way and that Charles will be the last King of many of these places before they become republics."
And the wave towards republicanism doesn't have anything to do with the popularity or personality of King Charles, the professor noted.
"I think it is inevitable that the British monarchy will cease to be associated with at least the vast majority of overseas independent nations. So we may never get to William succeeding to Charles as head of state in any of those realms," Walkling continued.
The current Prince of Wales would not be able to reflect the national psyche in, for example, Jamaican or Australia in the same way a head of state born and bred in these nations could, Professor Walkling said.
In the UK, on the other hand, the British monarch is vital for both the national pride and national psyche, the expert added.
"That's a little bit less applicable to, you know, Canadians, Australians, Jamaicans, they have a better justification for saying, well, it's not really our national psyche,"Andrew Walkling