LONDON - Extracts of intimate letters from Princess Diana to Dodi al-Fayed were read out at an inquest into her death on Friday, showing that the couple's relationship was serious and not just a holiday fling.

In one letter Diana thanks "Darling Dodi" for a holiday on his yacht, adding "This comes with all the love in the world and as always a million heartfelt thanks for bringing such joy into this chick's life."

In another exchange, dated August 13, 1997 -- just weeks before the couple were killed in a Paris car crash -- Diana sent him some cufflinks which had belonged to her father.

"Darling Dodi, these cufflinks were the very last gift from the man I loved most in the world, my father," her letter said.

"They are given to you as I know how much joy it would give him to know they were in such safe and special hands. Fondest love, Diana."

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

Al-Fayed alleges the killing was ordered because the couple were about to announce their engagement and Diana was pregnant. He claims the royal family did not want the mother of the future king having a child with his son.

Michael Mansfield, the lawyer representing al-Fayed at the inquest, produced the extracts from the letters as he quizzed the princess's friend and close confidante, Rosa Monckton, about the couple's relationship.

On Thursday, Monckton, who went on a Greek sailing holiday with Diana just two weeks before she died, had poured scorn on reports the princess had been pregnant and suggested Diana was still pining for her former lover, heart surgeon Hasnat Khan.

"She was treating this relationship with Dodi as a serious matter wasn't she? It doesn't suggest it was little more than a fling after a couple of days," Mansfield asked her.

Monckton replied that Diana tended to speak and write in an extravagant way but agreed the letters were not just written to make someone happy.

However, she rejected suggestions that Diana has misled her about her feelings for al-Fayed and that she had ended the relationship with Khan because she was in love with Dodi.

"She was not misleading me," said Monckton who broke down in tears during the cross-examination.

"We talked about it a lot. She told me Hasnat would never have her back once the photographs of her with Dodi had appeared and she was very upset about it."