Charles’ comments are due to be delivered during the opening ceremony of a summit of Commonwealth prime ministers and presidents in Rwanda, when he will say a long life has taught him these fundamental changes can be made “calmly and without rancour”.
But his observations are likely to be interpreted as acknowledging forces already in motion as a number of Caribbean nations have already suggested they may ditch the British monarchy and elect their own heads of state.
He is representing the Queen at the Commonwealth Heads of Government Meeting (Chogm), but his visit has been overshadowed by a row over reported comments he made criticising the Government’s scheme to send asylum seekers to Rwanda.
The prince’s office Clarence House has refused to be drawn on the comments of Boris Johnson who on Thursday appeared to take a veiled swipe at the prince and those who have attacked his plans to forcibly remove migrants to Rwanda.
Mr Johnson said ahead of a meeting with Charles later on Friday: “People need to keep an open mind about the policy, the critics need to keep an open mind about the policy.”
In response, a Clarence House spokesman said: “As we have said previously, we will not be commenting on supposed remarks made in private except to say that the prince is politically neutral. Policy is a matter for Government.”
In his address at the opening ceremony, Charles is expected to say: “The Commonwealth contains within it, countries that have had constitutional relationships with my family, some that continue to do so, and increasingly those that have had none.
“I want to say clearly, as I have said before, that each member’s Constitutional arrangement, as republic or monarchy, is purely a matter for each member country to decide.
“The benefit of long life brings me the experience that arrangements such as these can change, calmly and without rancour.”
Barbados took the historic move of replacing the Queen as head of state in November last year and elected its first president during a ceremony witnessed by the prince.
The Duke and Duchess of Cambridges’ March visit to the Caribbean appeared to raise the issue of other realms – nations where the Queen is head of state – breaking away from the British monarchy.
Jamaica’s prime minister Andrew Holness, who has travelled to Rwanda for Chogm, suggested to the couple his country may be the next to become a republic.
While a few days after the Cambridges left Belize, Henry Charles Usher, minister for constitutional and political reform, reportedly told Belize’s parliament: “Perhaps it is time for Belize to take the next step in truly owning our independence. But it is a matter that the people of Belize must decide on.”
Charles is also expected to say: “But as I said in Barbados last November, we should never forget the things which do not change: the close and trusted partnership between Commonwealth members; our common values and shared goals; and, perhaps most importantly, the strong and enduring connections between the peoples of the Commonwealth which strengthen us all.”
The prince will highlight one of the basic principles of the family of nations – how all members have the same standing: “Our Commonwealth family is – and will always remain – a free association of independent self-governing nations.
“We meet and talk as equals, sharing our knowledge and experience for the betterment of all citizens of the Commonwealth – and, indeed, the wider world.”
Before the opening ceremony in the capital Kigali, Charles, who has been joined by the Duchess of Cornwall, will meet the Rwandan president Paul Kagame and First Lady Jeanette Kagame, Commonwealth Secretary-General Baroness Scotland and Mr Johnson and his wife.
After the “family photo” of world leaders, Charles and Mr Johnson are scheduled to have their catch-up meeting but it is understood, despite suggestions form the prime minister, the two men are unlikely to discuss the controversial migrants policy.
The three topics on the agenda are sustainability, youth – including the work of the Prince’s Trust International and the fact that 60% of the Commonwealth’s population is aged under 30 – and the history and values of the Commonwealth and Charles’s passion for it.
During Friday the prince will host a reception for up to 25 new heads of government and later hold bilateral meetings with leaders at the venue for the opening ceremony, the Kigali Convention Centre.
The royal couple’s visit to Rwanda on behalf of the Queen, will end when they host a Chogm dinner for the visiting world leaders.