In his latest biography, Battle of Brothers, Mr Lacey bolsters rumours of conflict between Prince William and Prince Harry by narrating the perceived breakdown of their relationship.
He warns that the royal family could be changed forever if Harry and William don’t repair their relationship while Harry is said to have “realised there was something rotten at the heart of royalness.”
The biography paints a bleak picture of inter-family relations, meticulously drawing upon moments to claim that the royal family is in a time of crisis.
In an interview with the Daily Mail, Mr Lacey says Harry and William’s relationship crucially “matters” for the future of the Royal family.
He added: “It’s a question of values, even about the national morale. The idea of our modern royalty was built on the idea of these two brothers.”
Lacey claims that the royal family believe the Sussex Royal trademarked products, such as pencils and socks, are “commercialising the crown.”
Moreover, the biography contends that the Queen failing to have a picture of Harry, Meghan and their son Archie on the table during her 2019 Christmas broadcast is further evidence of a royal family in conflict.
Lacey adds that during Harry and Meghan’s tour of Africa last September, the Queen, Prince Charles and William were blindsighted and not consulted over the multiple legal actions announced by the couple against the media during the tour.
The biography says a “powerful constituency” inside Buckingham Palace, spearheaded by the Queen’s private secretary Sir Edward Young, believe that Meghan’s much talked about interview with ITV’s Tom Bradby in Africa showed a “bizarre tone-deafness” while being “miserably self-indulgent.”
Mr Lacey, who has previously written biographies on the Ford family and Sir Walter Raleigh, claimed “Meghan had gone into negative ‘victim’ mode.”
Meanwhile, Lacey hints the Royal family make a mistake in not seeing Markle’s race as something of an asset to the palace. “With Meghan, the royal family had a mixed-race recruit,” he writes, “for a monarchy that represents a mixed-race nation and a mixed-race commonwealth this was important.”
Other details noted by Lacey include Harry lunching with the Queen alone in January before the Sandringham Summit as William was reportedly “furious with Harry” following the couples announcement they would be leaving Britain to “carve out a progressive new role within this institution” and to become “financially independent."
Lacey maintains that the second-born royal is always treated badly, “not to say cruelly” he writes. “It happened with Princess Margaret. It happened with Prince Andrew,” he adds. “It’s the classic heir and the spare thing… And they certainly didn’t know what to do with the spare's wife.”
The book, reportedly written over a number of months and after conversations with senior palace sources, claims tensions rose in the family as the “Sussexes wanted guarantees on every single point as if it were a contractual negotiation.”
Mr Lacey first rose to prominence in 1977 with his biography of Queen Elizabeth II and notably works as a consultant on the Netflix show The Crown.
Lacey’s critical lens follows on from Carolyn Durand and Omid Scobie’s flattering biography of the Sussexes, Finding Freedom, released over the summer, which gave a detailed account of the couple’s relationship.