The intimate notes were disclosed for the first time, shortly before the hearing was told that it would be given a secret recording of Dodi breaking up with his former fiancee. Both exchanges date from mid-August 1997.
More than 10 years after Diana and Dodi were killed in a car crash in the Alma tunnel in Paris, the emotional turmoil generated by their deaths was sufficient to reduce one witness to tears and bring another to the verge of distress.

Rosa Monckton — the princess’s confidante who is married to Dominic Lawson, the former editor of the Sunday Telegraph, was asked to comment on two letters sent by Diana to Dodi after they had holidayed together on his father’s yacht off St Tropez.

The passages were read by Michael Mansfield QC, representing Mohamed Al Fayed, the owner of Harrods, and Dodi’s father. The revelation was intended to emphasise the family’s case that the couple were deeply attached.

In one letter, thanking “Darling Dodi” for a six-day holiday on his yacht, Diana wrote, “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, sending him cufflinks, she wrote, “Darling Dodi, these cufflinks were the very last gift from the man I loved most in the world, my father.

“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.”

Mansfield said, “She was treating this relationship with Dodi as a serious matter, wasn’t she? It doesn’t suggest that it was little more than a fling after a couple of days.”

But Monckton replied, “It’s a thank you letter. She tended to speak and write in an extravagant way.”

Earlier, she gave evidence that the princess would still have been going out with the heart surgeon, Hasnat Khan, but he could not bear the pressure of publicity.

Pressed by Mansfield about whether she had been told everything by her friend or could have misinterpreted what was said, Monckton, in tears, said, “Diana was a very good friend of mine for six years. She was godmother to my handicapped daughter and was by my side when I buried my other daughter.

“She was a very true and a close friend. But that doesn’t preclude her from not telling me certain things. You don’t tell people everything the whole time.”

Unscheduled evidence on Friday from the American model Kelly Fisher, Dodi’s ex-fiancee, exposed the bitterness of their break-up, which coincided with the start of his affair with Diana.

Fisher told the inquest that she had recorded a telephone call with Dodi in mid-August 1997 after pictures had been published showing Dodi and Diana kissing.

The tape, she said, is kept in a safe deposit box in the US but she would present it to the inquest.