In an electric exchange between Burrell and Michael Mansfield QC, barrister for Dodi’s father Mohamed Al Fayed, the jury sat rapt as the lawyer teased the startling revelation from the former butler.

Mr Mansfield asked Burrell: “She (Shand Kydd) had expressed herself in extremely forceable terms about Diana’s consorts, particularly if they were Muslim, hadn’t she?” Burrell agreed that was correct.

“Was one a phone call you overheard and the other was in your presence or what?” asked Mr Mansfield. “They were both phone calls,” said Burrell.

Mr Mansfield then asked: “How is it you know about them?” “Because I sat and listened with the Princess’s ear on one side and mine on the other. It was shared, an old-style phone,” he replied.

“What view was she expressing about the possibility of a Muslim partner for Diana?” Burrell was asked. He replied: “She wasn’t very happy.”

Displaying his irritation with Burrell’s evasiveness, Mr Mansfield stressed: “I want to spell it out, please, because it’s being suggested that, in fact, everything would have been fine as far as the family were concerned about Diana marrying Hasnat Khan. What did Shand Kydd say, please?”

Burrell replied: “Well, I don’t, respectfully don’t think that’s very kind to a lady who is no longer here.”

Mr Mansfield countered: “If you would be very kind and just indicate – you realise this is an important issue for this jury – the extent to which the relationship with Dodi Fayed and particularly obviously his father, how it may have been viewed. Do you follow?” “I do,” said Burrell.

Mr Mansfield, pressing again, asked: “What was it that she said, because she may have said it to other people in the Royal Family. You mentioned her when you went and saw the Queen, didn’t you?” “Yes”.

At this point the coroner, Lord Justice Scott Baker, warned Burrell: “This is relevant,” prompting the former servant to drop his bombshell. To a hushed courtroom, he said: “Well, she called the Princess a whore and she said that she was messing around with effing Muslim men and she was disgraceful and said some very nasty things.” Mr Mansfield: “It was as a result of at least one of those calls that the Princess decided she really didn’t want to talk to her mother again?”

“Yes,” replied Burrell, before adding that the conversations between Diana and her mother took place before her relationship with Dodi flourished.

When pressed on Diana’s fears for her life, Burrell said it was impossible that Prince Philip would have wanted to have her murdered.

He told the jury: “Knowing the members of the Royal Family so well, I think that’s impossible.” He added: “The Princess always had a great fondness for Prince Charles. Prince Charles was not capable of murdering the Princess.”

But Burrell refused to discuss the meaning of the last letter Diana wrote to him, when she was heavily involved with Dodi and referred to a secret.

He included the letter in a book about the Princess but yesterday coyly refused to be drawn on its meaning.

Eventually he claimed that, although he knew many of Diana’s secrets, he was not sure which one this was and then admitted: “I cannot remember what that particular secret was.”