Buckingham Palace has forcefully denied a claim by the brother of the late Princess Diana that King Charles III said his ex-wife would soon be forgotten after her death. In a new book, Charles Spencer recounts the traumatic days after Diana was killed in a car crash in Paris in 1997 at the age of 36. He alleges that he argued with his sister’s former husband over palace plans for Prince William and Prince Harry, then aged 15 and 12, to walk behind her coffin during the funeral...