Imran Khan: I was Diana's go-between

By Andrew Alderson

"She had been involved with him for two years and she had wanted to marry him. It was clear that she was very deeply in love with Dr Hasnat and I just don't think she could have got over it that quickly," said Mr Khan. Mr Khan says that the heart surgeon, who lives in Chelsea, is shy, dignified and reserved. "These factors must have attracted her," he said. "She had decided he was the man she wanted to live with."

When the Princess and Dodi Fayed were killed in a car crash in August 1997, the cricketer-turned-politician had already made plans to fly to London from Lahore, and intended to meet Dr Khan. Having married Jemima Goldsmith, the British daughter of the late financier Sir James Goldsmith, Mr Khan understood the difficulties of a mixed marriage.

"I had it in my mind that I was going to talk to him. At least to find out what was the reason [for his reluctance to marry her] because maybe there was some reason that she [the Princess] wasn't aware of. Maybe I could speak to him because having married someone from outside my culture, if there was something that could be cleared or some advice that could be given, then maybe I would be able to help." Only the death of the Princess ended his mission as the go-between. "Before that could happen, that tragic incident took place," he says.

The documentary, Diana: Her Last Love, to be shown on Channel 5, discloses that even during her summer fling with Dodi Fayed, the Princess was in touch with Dr Khan's family telling them not to read anything significant into the relationship. The programme suggests that Dr Khan had ended their relationship in July because he disliked the media attention that surrounded her every move, and because his strict Muslim family - who were accustomed to arranged marriages - found it impossible to accept a divorced Western women into the fold, even if she was a British princess. The Princess refused to accept his decision was final, however, and sought to convince him that, given time, their relationship could work.

Shortly after the Paris crash, Mr Fayed claimed that his son and the Princess were planning to marry and that he had bought her an engagement ring even though their intimate relationship had lasted less than a month. However, former staff of the Harrods owner have dismissed his claims, insisting that Mr Fayed exaggerated the importance of the summer romance.

In the documentary, members of Dr Khan's family speak openly of his love for the Princess. Ashfaq Ahmed, his great-uncle, says: "I can say with certainty that he was greatly in love with her, and he was very much impressed by her personality. Not by her beauty - by her humanity." On September 6, 1997, a week after the death of the Princess, Dr Khan made a discreet appearance at her funeral service in Westminster Abbey. He sat with his head bowed, wearing dark glasses and overcome by grief.

Dr Khan, 40, who works with Professor Sir Magdi Yacoub at Harefield Hospital in Middlesex and the Royal Brompton Hospital in London and , has never spoken publicly about his relationship with the Princess. His family and friends are convinced that he never will.