Former royal butler Paul Burrell has said he does not "support or endorse" the Daily Mirror's naming of the royal Diana thought was plotting to kill her.
Paul Burrell's book caused a media storm
The newspaper identified Prince Charles as the figure alleged in a letter from Diana to be planning a car crash.
Mr Burrell said: "It was always my intention never to publish that name."
Mirror editor Piers Morgan said he had known Mr Burrell would not be happy about the revelations which Mr Morgan admitted were probably "preposterous".
There is no evidence to support the allegation about Charles in the letter, which was written by Diana 10 months before her death.
It was published in the butler's book A Royal Duty, but a passage was blanked out by the publishers Penguin and the Daily Mirror, which serialised the work.
But on Tuesday, the Mirror revealed the blanked-out passage read: "This
particular phase in my life is the most dangerous - my husband is planning 'an
accident' in my car, brake failure and serious head injury in order to make the
path clear for him to marry."
There have been a number of conspiracy theories surrounding Diana's death, but the French investigation blamed the crash on driver Henri Paul, who was speeding and had been drinking, while others have pointed to the fact the only person wearing a seatbelt in the car, Trevor Rees Jones, survived.
A statement released through Mr Burrell's agent Ali Gunn read: "As the editor of the
Daily Mirror will confirm, Mr Burrell never wanted any new information to be
published following the serialisation of his book.
"Today's publication was solely a decision taken by the newspaper without Mr
Burrell's knowledge or consent.
"He was only informed late on Monday evening and he does not support or endorse its publication.
"The Daily Mirror only became aware during the photographing of the letter for its book serialisation last October of certain sensitive information.
"Mr Burrell could not have made it clearer that he did not want any new
information to be published then or in the future."
Speaking to Sky News outside his home in Farndon, Cheshire, Mr Burrell said:
"I'm not happy about it. I only learned about it late last night and it was
always my intention never to publish that name. I never ever wanted it to be
Daily Mirror editor Piers Morgan was bullish about the publication of Prince
Charles's name, saying the coroner's request for the letter meant it was likely to be revealed anyway at the inquest.
"Paul Burrell was not aware of what we were doing. I knew he would not be very happy about it."
On the letter, he said: "Is it preposterous? Probably. I just don't know."
Prince Charles's former press secretary Colleen Harris said the allegation was "preposterous" and "absolute nonsense".
"Anyone that works for the Prince or knows him will think this is complete
and utter rubbish, it is unbelievable," she told BBC Radio 4's The World At One.