Late Princess Diana’s brother claims King Charles told him, “we’ll forget her soon enough” before funeral

London — Nearly 30 years after Princess Diana died in a car crash in Paris, her brother is making new claims about the way he says she was mistreated by Britain’s royal family — even as they planned her funeral.

Buckingham Palace is suggesting he got it wrong, with his recollections clouded by grief.  

“I felt it my duty to lay out the true story of Diana in one book,” Charles Spencer, Diana’s younger brother, told CBS News. He will outline his new claims in an exclusive interview on “CBS Sunday Morning” this weekend.

In “Swan Song: Diana, My Sister,” set to be published next week, Spencer writes that he told King Charles III, who was then Prince Charles, he objected to the plan for her young sons Princes William and Harry to walk in her funeral procession.

Spencer says in his book, excerpts of which are being published by the Daily Mail tabloid in Britain, that the then Prince Charles responded to his objection by questioning his family’s sense of duty, and telling him: “Rest assured, we’ll forget her soon enough.” 

The young princes, then 12 and 15, did join the procession, yielding images of the two boys walking behind their mother’s coffin that have endured to this day.

Spencer accuses the now-British monarch of having “contempt” for his ex-wife.

Buckingham Palace responded with a terse statement Wednesday evening, which avoided calling Spencer a liar, but said the king “is mindful that the pain of fraternal grief can cloud reason, affect judgement and colour memory.”

The unprecedented outpouring of grief for Diana in 1997 led to harsh criticism of the royal family, with many feeling they appeared not to understand the nation’s, and indeed the world’s, pain over her death. 

It quickly became a public relations disaster for the palace, one it has struggled to get past for three decades.

“They will never be able to lay Diana to rest,” CBS News royal contributor Roya Nikkhah said Thursday, “because the memory of her continues to occasionally haunt the royal family.” 

Nikkhah, who is the Royal Editor for The Sunday Times newspaper, said the king’s family was in for “a very tricky few days,” predicting that Spencer’s claims about what the king said after Dana died would be “just the beginning of a serialization that will go on … and we know there are going to be some pretty sensational claims” ahead of the book’s release next week.

“That is going to put Buckingham Palace into reactive mode,” Nikkhah said. “They will have to decide whether or not they’re going about each and every claim, or just to make that first response we’ve heard from the palace their definitive response. But it’s going to put them into fight mode, and it’s going to be very difficult for the king.” 

The British royals already had a lot on their plate before Spencer’s new claims started to emerge. 

King Charles is still receiving treatment for an unspecified form of cancer, and his daughter-in-law Catherine, the Princess of Wales, is recovering after her own treatment for the disease.

Prince Harry and Meghan’s recent return to the U.K. from California, meanwhile, has renewed attention on their long-running schism with the rest of the royal family.