Prince Charles is likely to be interrogated by British police following sensational allegations that his divorced wife Princess Diana was murdered at his behest.

The heir to the British throne is expected to be asked by the police to comment on a handwritten note in which the princess suggests that her former husband wanted her dead.

The police investigation into Diana's death was confirmed on Tuesday by Britain's royal coroner as he formally opened and adjourned inquests into the deaths of Diana and her lover, Dodi Fayed, in a car crash in Paris in August 1997.

Coroner Michael Burgess said he had asked the Met's Commissioner, Sir John Stevens, to probe speculation that their deaths were not the result of a 'straightforward, road traffic accident'.

The investigation was announced as it emerged Diana had written a letter 10 months before she died saying she believed Prince Charles was planning 'an accident' for her car with the intention of causing 'serious head injury in order to make the path clear for him to marry'.

The letter was published in a book by Diana's former butler, Paul Burrell, last year, but the reference to Prince Charles had been blanked out.

Buckingham Palace has remained silent about the allegations contained in the letter but Charles's former Press aide, Colleen Harris, condemned the contents as 'preposterous' and 'absolute rubbish'.

Burrell, to whom the letter was written, said he was not happy about its complete contents being made public. "It was always my intention never to publish that name," he said.

The coroner did not mention the letter as he opened the inquest into Diana's death in London, but it is understood that he has formally requested it from Mr Burrell. He later opened a separate inquest into Dodi's death.

In a statement read at both hearings, Burgess said, "I am aware that there is speculation that these deaths were not the result of a sad, but relatively straightforward, road traffic accident in Paris. I have asked the Metropolitan Police Commissioner to make inquiries.

"The results of these inquiries will help me to decide whether such matters will fall within the scope of the investigation carried out at the inquests."

Scotland Yard, meanwhile, has confirmed that a senior police officer named as Commander David Armond will lead the Diana inquiry. His team will interview possible witnesses, including Prince Charles and his sons, to find out whether their evidence is relevant to the inquests, which will not resume until early 2005.

As the hearings were adjourned on Tuesday Dodi's father Mohamed al Fayed maintained his son and Diana were victims of a 'horrendous murder'.

The opening of the inquest was the first official public hearing in Britain into Diana's death. Diana, 36, and Dodi, 42, were killed with chauffeur Henri Paul when their Mercedes crashed in Paris on August 31 1997.

A two-year investigation in France blamed Paul for losing control of the car because he was high on drink and prescription drugs and driving too fast.

Burgess has yet to receive the 6,000-page document produced by French investigators.

In an apparent reference to Diana's sons, William and Harry, the coroner spoke of his regret at the 'untold pain' that some would face in having to relive the deaths through an inquest.

"While the inquest process and hearings may offer some insight into the factual circumstances as to how the cause of death occurred, it may also give rise to considerable and possibly unnecessary intrusions into private grief.

"That I regret, just as I regret the untold pain for some in having to relive the experiences surrounding the death," he said.

He added the delay in launching the inquest was the result of an 'extremely lengthy' and detailed French judicial investigation, which was only now drawing to a close. It would have been 'desirable' for the inquests to have been heard and completed long ago, he said.

Burgess also spoke of how the bodies of Diana and Dodi arrived in England on August 31, 1997 and of how Mr Al Fayed had wished for his son to be buried before nightfall.

A post-mortem examination was carried out on Diana, and a certificate issued for her burial. In an apparent reference to rumours of a cover-up regarding allegations Diana was pregnant, Mr Burgess said of the post-mortem examinations: "At no time did the pathologist receive any instruction or direction from anyone other than Dr Burton (the former Royal coroner) and me regarding these examinations."

For his part Dr Burton has declared that Diana was not pregnant at the time of her death. He told The Times newspaper, "I was actually present when she was examined. She wasn't pregnant. I know she wasn't pregnant."