Prince William's emotional appeal to Queen Elizabeth II revealed

Prince William, heir to the British throne as the eldest son of King Charles III, urged his grandmother Queen Elizabeth II to intervene in the Scottish independence referendum, a new book has claimed.

The late Queen, who reigned for more than 70 years until her death at the age of 96, responded by saying that the people of Scotland would "think very carefully about the future" just days before the referendum.

Sources at the time said that the late Queen’s comments were spontaneous. It happened when some polls showed that the Yes vote was ahead.

However, David Cameron, who was Prime Minister at the time, has previously confirmed that he lobbied the monarch to intervene.

Valentine Low in his new book, Power and the Palace, wrote: “The pressure (on the Queen to intervene) did not just come from Cameron, however. Prince William also wanted the Queen to say something, and urged the Queen’s private secretary, Sir Christopher Geidt, to get her to intervene."

The author went on: “Geidt and the cabinet secretary, Sir Jeremy Heywood, had... already been talking about the constitutional propriety of an intervention by the monarch, and between them they came up with the formula that the Queen would use when she stopped to talk to members of the public outside Crathie Kirk that Sunday.”

The No campaign received 55 per cent of the vote in the referendum, meaning Scotland remained part of the United Kingdom.

The book also claims that Queen Elizabeth II had no enthusiasm for making a change to a royal family rule that would allow princesses to take the throne. In 2013, the law was changed to ensure the firstborn child of a monarch would be next in line to the throne regardless of their gender.

Previously, the firstborn son of a monarch would jump ahead of any elder sisters they may have in the Royal Family’s line of succession.