Cookies’ favourites for boys’ names are Arthur, Philip and Albert. All are highly traditional royal names and it is thought the couple will not opt for a more modern option reflecting the Middleton side of the family.
The boy will share a birthday with St George’s Day.
The Queen and the Duke of Edinburgh, the boy’s great-grandparents, as well as Prince Charles, the Duchess of Cornwall, Prince Harry and members of both families ‘have been informed and are delighted with the news’, the palace said.
It is highly unlikely the baby, as the third child, would ever accede to the throne. It is yet to happen in the current House of Windsor and the last time it happened was when the third child of George III and Queen Charlotte, William IV, became king and ruled from 1830 to 1837.
Under previous rules the baby prince would have leapfrogged his older sister Charlotte to become fourth in line to the throne. But the Succession to the Crown Act 2013 removed the automatic preference for male offspring, meaning royal children now inherit the throne in strict order of birth.