The monarch wrote a lengthy letter to the U.S. president, while Prince Harry took a veiled swipe at him during a speech.

Prince Harry made subtle criticisms of President Trump's administration during a speech at the Upfront Summit in Los Angeles on Thursday. The Duke of Sussex insisted he is not on the "left or right" side of politics whilst making remarks that appeared aimed at the current US leadership.

Prince Harry has had many monikers given to him by royal family members and admirers. However, not all have been to his liking. In his memoir Spare, Harry disclosed his long-standing annoyance with one particular nickname.