Buckingham Palace has strongly pushed back against claims made by Earl Spencer in his upcoming memoir, suggesting that the late princess's brother has had his memory clouded by grief.

We did not previously know how the royal household would respond to Spencer's claims. In a statement, a palace spokesperson said: "While we do not comment on books as a matter of principle, His Majesty is mindful that the pain of fraternal grief can cloud reason, affect judgment and colour memory in ways others do not recognise, even many years after such a loss."

The response follows published extracts from Spencer's forthcoming book, Swan Song: Diana, My Sister, in which he recounts telephone conversations with the royal household following Diana's death in Paris on 31 August 1997.

In the book, Spencer alleges that King Charles, who was then the Prince of Wales, sounded "giddily elated – like a lottery winner" when calling him at his home in Cape Town, South Africa, after the crash. Spencer also claimed Charles said of Diana: "We'll forget her soon enough."

The published extracts further suggest that some figures within Buckingham Palace felt "relieved" following Diana's death.

Beyond the phone calls, Spencer outlines his recollection of the arrangements for the funeral. He writes that he believed the palace wanted Prince William, Prince Harry, and himself to walk behind Diana's coffin during the procession.

According to Spencer, the then prince was "adamant" that he would walk behind the coffin. Spencer claims palace officials backed the plan out of concern that members of the public might shout abuse at Charles if he walked alone or without Diana's family beside him.

Representatives for Prince Harry have said they do not wish to comment on the book, while Buckingham Palace has pointed back to its rejection of the claims.

The book is scheduled for publication next week. I'll continue tracking developments as further details emerge.