Queen Elizabeth II is reportedly not on the best terms with Prince Charles, her eldest son, and her successor to the British throne.

In Channel 4's new documentary titled "Love, Honour, and Crown," multiple royal experts spoke of differences between the monarch and the heir apparent. Clive Irving, the author of the new biography "The Last Queen," claimed that the Queen is "constantly frustrated" with the Prince of Wales who will "never live up to her sense of duty," reports Mail Online.

Irving also said that the 94-year-old has "never really understood" Charles and feels "puzzled by him." He added that the only royal who fully appreciates her "very dedicated sense of duty" is her grandson Prince William, the eldest son of Charles and second in line to the throne.

"All those around the Queen never measure up to that at any point. Her own family has not measured up to that. Charles never measures up to that," Irving said.

The author also claimed that the monarch is more drawn to her second son Prince Andrew, who stepped down as a working royal in 2019 due to public uproar surrounding his alleged involvement with convicted sex offender Jeffrey Epstein. "To this day, she's more openly affectionate to Andrew and more forgiving toward Andrew than she is towards Charles," Irving said.

Royal expert Ingrid Seward also reflected similar sentiments, noting that the two brothers are the "polar opposite" of one another. "He's [Andrew] noisy, bumptious, very charming, when he wants to be. He can be arrogant and rude; he has some characteristics of his own father," she said, adding that the queen is particularly "proud" of his service in the Navy, including the Falklands War where he ensured he had returned "like a war hero." The war took place when Charles and Andrew were first and second in the line of succession to the British throne respectively and represented "everything the monarchy could be."

Channel 4's documentary, described as an "in-depth examination of several dramatic conflicts between Crown and Family during the Queen's long reign," also looks at the monarch's early romance with Prince Philip, her husband of 73 years, and the role he played in modernising the monarchy. The programme also features now-declassified documents, including one that shows the Queen's efforts to ensure that her only sibling Princess Margaret could marry Group Captain Peter Townsend, a divorcé who was equerry to their father King George VI.

The late Princess Margaret, then third-in-line to the throne, needed the consent of the Queen and the Prime Minister to marry, that her sister wasn't able to give as she was the head of the church of England which didn't allow a divorcé with a living spouse to remarry. However, the queen struck a deal with the then PM Anthony Eden to help her sister, who eventually called off the wedding.

queens speech
Queen Elizabeth II and Prince Charles, Prince of Wales arrive in the House of Lords for the Queen's Speech Getty