Buckingham Palace tonight accused Earl Spencer of ‘grief clouded reasoning’ after his incendiary claims about the days after Diana’s death were revealed by the Mail.

The Earl claims a furious Prince Charles told him days after Princess Diana’s death, ‘rest assured, we’ll forget her soon enough’, in a devastating memoir to be serialised in the Daily Mail from tomorrow.

The Palace issued an extraordinary statement last night that 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.’

In allegations that will send shockwaves through the Royal Family, Charles Spencer’s bombshell book lifts the lid on an incendiary row with the now King over Diana’s funeral arrangements.

The argument followed the decision, opposed by Diana’s brother the Earl, that Prince William and Prince Harry, then aged 15 and 12, would walk in their mother’s funeral procession.

The earl says he insisted to the then Prince of Wales that Diana would not have wanted her young sons to endure such a public ordeal.

It is claimed Charles then questioned the Spencer family’s sense of duty before saying his former wife, whose death sparked a global outpouring of grief, would soon be forgotten.

The Prince and Princess of Wales attend a welcome ceremony in Toronto at the beginning of their Canadian tour in October 1991

Charles Spencer, the ninth Earl Spencer, delivers his famously defiant eulogy at his sister’s funeral

The astonishing account of the King’s alleged outburst almost 30 years ago is included in Swan Song: Diana, My Sister, which Earl Spencer, 62, says he has written to correct ‘untruths’ told about his older sister.

The exclusive serialisation will begin on dailymail.com later today.

The book includes a string of further extraordinary claims about Diana’s failed marriage to Charles and the tumultuous aftermath of her tragic death in a car crash in Paris in 1997.

The revelations are set to plunge Buckingham Palace into a fresh storm just weeks after the return of the Duke and Duchess of Sussex and their children to the UK from California. 

On September 6, 1997, six days after Diana’s death, Earl Spencer delivered a defiant eulogy at her funeral that was later named one of the greatest speeches of the 20th century.

His raw oration in Westminster Abbey was delivered after he walked alongside William and Harry, as well as Prince Charles and Prince Philip, behind Diana’s coffin in a funeral procession through central London.

In his book, Earl Spencer writes that when one of Queen Elizabeth’s most senior aides told him in the days before the funeral that William and Harry would take part in the procession, he responded: ‘That’s not going to happen.’

But minutes later he received a phone call from Prince Charles who insisted that 18 years earlier he had walked in the funeral procession of Lord Mountbatten, his great-uncle.

From left, the Earl, Prince William, Prince Harry and Charles at Diana’s funeral on September 6, 1997

The Earl, Diana and Charles at the Earl’s 21st birthday party in 1985 at the Mirabelle restaurant in London

The memoir describes how Charles ‘went nuts’ after the earl pointed out that the prince had been 30 at the time of Lord Mountbatten’s funeral in 1979.

In one of the book’s most extraordinary passages, Earl Spencer writes: ‘Prince Charles continued his stream of anger, without me interrupting. Then he stopped.

‘I assumed the pause signalled an effort to bring himself under control, but then he unleashed down the phone what I have always taken to be his pent-up contempt for Diana, and his horror that the world was so bowled over by her death. “Rest assured,” he hissed, “we’ll forget her soon enough!”.’

Earl Spencer said that he was ‘so stunned’ by the alleged remarks that he took a few seconds to reply.

‘“I can’t believe you just said that,” I said flatly, before hanging up,’ he writes.

Described as ‘historic’, Swan Song is due to be published worldwide next Tuesday – in the UK by Penguin Michael Joseph, a division of Penguin Random House – with the Daily Mail’s exclusive serialisation starting tomorrow.

Police in the Netherlands are still investigating what publishing sources say is the ‘extremely suspicious’ overnight theft of four copies of the book from the back of a parked lorry earlier this week.

• Read the first extract from Earl Spencer’s bombshell book on dailymail.com at 5pm UK time on Thursday (12pm in New York, 2am Friday in Sydney) 

Extracted from Swan Song: Diana, My Sister by Charles Spencer, to be published by Michael Joseph on September 22, £28. © Charles Spencer 2026. To order a copy for £23.80 (offer valid to 10/10/26; UK P&P free on orders over £25) go to www.mailshop.co.uk/books or call 020 3176 2937.