LONDON - Princess Diana thanked her father-in-law Prince Philip for trying to save her crumbling marriage and praised his skills as a counsellor, the inquest into her death was told on Thursday.

Letters between the two, heavily edited to remove personal details, were presented to the inquest jury investigating the death of Diana and her lover Dodi al-Fayed in a Paris car crash in August 1997.

Dodi's father Mohamed al-Fayed, owner of Harrods, says Diana and his son were killed by British security services on the orders of Prince Philip.

The "Dearest Pa" letters were produced in court by Brigadier Sir Miles Hunt-Davis, Prince Philip's private secretary, who said there was nothing derogatory in the 1992 correspondence. Diana and Prince Charles were divorced in 1996.

The inquest was told press reports had alleged Philip had written "unpleasant, nasty and insulting" letters to Diana. But the excerpts produced in court painted a different picture.

Philip wrote in one typewritten letter: "If invited, I will always do my utmost to help you and Charles to the best of my ability, but I am quite ready to concede that I have no talents as a marriage counsellor!!!"

In her handwritten reply, Diana said: "Dearest Pa, I was particularly touched by your most recent letter which proved to me, if I didn't already know it, that you really do care.

"You are very modest about your marriage guidance skills and I disagree with you."

Fayed alleges the killing was ordered because the royal family did not want the mother of the future king having a child with his son. He says Diana's body was embalmed to cover up evidence she was expecting a baby.

Rosa Monkton, one of Diana's closest confidantes, told the court that she and her husband, journalist Dominic Lawson, had helped Diana draft the replies to her father-in-law.

Monkton, who went on a Greek sailing holiday with Diana just two weeks before she died, poured scorn on reports the princess had been pregnant.

"She could not possibly have been pregnant. While we were on the boat, she had her period and that was just 10 days before she died," Monkton said.

She felt Diana was still pining for her former lover, heart surgeon Hasnat Khan, who had just split up with her.

"It was clear to me that she was really missing Hasnat and that I think Dodi was a distraction from the hurt that she felt from the break-up of that relationship," she said.

Monkton also described as "absolute fantasy" allegations by Mohamed al-Fayed that she had got to know Diana only so she could pass on information to British secret services.