Prince Philip will not have to give evidence to the inquest into the deaths of Princess Diana and her lover Dodi al-Fayed, the coroner said on Friday.

The Queen will not have to answer questions either.

"In my judgment it is not expedient to call the Duke of Edinburgh to give evidence, nor do I think the Queen should be asked to answer the questions by Michael Mansfield," the coroner, Lord Justice Scott Baker, said, referring to the lawyer for Mohamed al-Fayed, Dodi's father.

"Neither step will, in my judgment, further the inquest process."

Mohamed al-Fayed, an Egyptian-born retail tycoon, has always wanted Prince Philip to answer questions on his relationship with the princess, who died along with Dodi in a Paris car crash in 1997.

Al-Fayed accuses the royal family of wanting to "get rid" of Diana and has suggested that Prince Philip was behind the plot.

When he appeared before the inquest last month, al-Fayed was asked if Prince Philip was at the heart of the conspiracy.

"That's right," he said.

The inquest earlier heard, however, that Prince Philip and Diana had enjoyed a warm relationship, with the two exchanging letters as far back as 1992 and Diana referring to him as "Dearest Pa".

French and British police investigations have both concluded that Diana and Dodi died as a result of a tragic accident caused by a speeding driver who was found to have been drunk. Both inquiries rejected al-Fayed's theories.

The driver, Henri Paul, a Fayed employee, also died.