His younger sister, Lilibet “Lili” Mountbatten-Windsor, is also entitled to be a princess after the death and the accession of her grandfather Charles, the Prince of Wales, to the throne, The Guardian newspaper reported.

The Duke and Duchess of Sussex Harry and Meghan Markle will see no change in their Royal titles.

Meghan had spoken during an interview in March last year with the US broadcaster Oprah Winfrey of her shock at being told Archie would not get police protection because he did not have a title, and suggested that the decision was taken because of his mixed race.

The Sussexes indicated in the interview that they had expected Archie would be given the title of prince after Charles acceded the throne, but that they had been told that protocols would be changed – in line with Charles’s wish for a slimmed-down monarchy – so that the child would be excluded from becoming an HRH and prince.

Under protocols established by King George V in 1917, the children and grandchildren of a sovereign have the automatic right to the title Her Royal Highness or His Royal Highness (HRH) and prince or princess.

At the time Archie was born, he was the great-grandchild of a sovereign, not a grandchild. But to prevent him from becoming a prince, the King would have to issue a Letters Patent amending Archie’s right to be a prince and Lili’s right to be a princess.

George V’s declaration meant that only Prince George, as a great-grandson of the monarch down the direct line of succession to the throne, was originally entitled to be a prince, as he is the eldest son of the eldest son of the Prince of Wales.

The line of succession has also been reshuffled after the Queen's death, and sees Prince William move up to next in line for the throne, the Daily Star newspaper reported.

He is followed by Prince George (9), Princess Charlotte (7), Prince Louis (4), Prince Harry, and Master Archie, (3).