LONDON, United Kingdom (AFP)—Britain’s King Charles III has taken the rare step of hitting back at criticism after Princess Diana’s brother alleged that the monarch acted insensitively following her death in a car crash three decades ago.

The war of words between the king — who was married to Diana for 15 years — and Charles Spencer featured on the front pages of several UK newspapers on Thursday.

Buckingham Palace issued an unusually strong statement after Spencer claimed in his new memoir that days after Diana died in 1997 the future king said to him: “Rest assured, we’ll forget her soon enough.”

A palace spokesperson said late Wednesday they do not normally comment on books, before adding: “His Majesty is mindful that the pain of fraternal grief can cloud reason, affect judgement and colour memory in ways others do not recognise, even many years after such a loss.”

Spencer’s book, titled “Swan Song: Diana, My Sister” and set to be published next week, has been serialised in the Daily Mail newspaper.

In excerpts released so far, Spencer claims Charles subjected him to a “stream of anger” after he insisted Diana would not have wanted her sons, princes William and Harry, then aged 15 and 12, to walk in her funeral procession.

“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!’,” Spencer writes.

Diana, who was hugely popular in the UK, died in Paris aged 36 after the car she was travelling in crashed as it tried to get away from paparazzi photographers.

Her death sparked an outpouring of grief in Britain and led to accusations that the monarchy failed to show the appropriate empathy.

Both heir-to-the-throne William and his brother Harry, who quit royal duties in 2020 but has just returned to Britain, have spoken previously about how difficult it was to walk behind her coffin.

– ‘Recollections may vary’ –

Julian Payne, who was communications secretary to Charles on the 20th anniversary of Diana’s death in 2017, said he found it hard to believe his former boss had said what Spencer alleges.

“It’s just not language that I recognise,” he told the BBC.

Royal watchers said Buckingham Palace’s quick response to Spencer’s allegation hinted at the anger felt within the monarchy at the claim.

“Sometimes the palace have to weigh up whether or not they want to just leave things and adopt the never complain, never explain mantra,” Sunday Times royal editor Roya Nikkhah told the BBC.

“But I don’t think that would have washed in this scenario.

“It’s too big a claim. And they know with the serialisation there are days more of this kind of stuff coming and so they’ll be braced.”

UK media also likened the language in the palace’s statement to the late queen Elizabeth II’s response in 2021 to claims of racism in the royal family from Harry and his wife Meghan.

The queen said that “some recollections may vary”.

Charles and Diana’s tumultuous marriage between 1981 and 1996 was regularly featured in British newspapers, and continues to fascinate.

Diana’s famous “revenge dress” that she wore on the evening in 1994 that Charles made a public admission of adultery is to be auctioned in New York in December.