Prince Charles plans to ensure that his two-year-old grandson Archie will never become a prince, it has been reported.

The heir to the British throne is said to have proposed that Prince Harry’s children will not be given royal titles as part of plans for a smaller monarchy.

The proposal has angered Prince Harry and his wife Meghan Markle, according to The Mail on Sunday, and was one of the reasons behind their attack on the royal family during their interview with the US talk show host Oprah Winfrey.

The move by Charles, the Prince of Wales, is a break with precedent as a grandchild of the sovereign traditionally has the right to be a prince or princess.

Charles is said to have told Harry and Meghan, the Duke and Duchess of Sussex, that he would change legal instruments known as the Letters Patent to exclude Archie and others.

Charles's plan for a smaller monarchy has never been officially disclosed but it is understood that only the heir to the throne and their immediate families will receive full titles when he becomes king.

These royals will receive financial support from the public purse through the Sovereign Grant and personal security funded by nearly £70 million ($95.6m) of British taxpayers' money.

Charles apparently wants to limit the number of key royals to keep costs down for the public and ensure the monarchy’s continued popularity.

But the move is said to have infuriated the Sussexes, deepening their rift with the rest of the royal family.

The couple had made a point of not using a lesser title for their son, who is the Earl of Dumbarton, in the belief he would become a prince.

The couple, whose baby daughter Lilibet will not be given the title of princess, reportedly learnt about the decision before their interview with Winfrey in March, in which they alleged that a racist comment had been made by an unnamed royal.

The apparent move comes as the newly revised book Battle Of The Brothers, by the royal biographer Robert Lacey, has been published.

It claims that Prince William, whose children have prince and princess titles, decided to divide the Kensington Palace household after a “furious confrontation” with Prince Harry in 2018 amid allegations of bullying by Ms Markle.

She denies all allegations of bullying.