Ivan Fallon: A day on the Blue Train with Naomi and Nelson

The mise en scène was the railway station in Pretoria, early morning 26 September 1997. Nelson Mandela was three years into his presidency, at the very height of his international fame, the person everyone in the galaxy most wanted to meet. World leaders, royalty (the Queen, Prince Philip, Diana and even Fergie had all visited) and celebrities of every kind and hue journeyed to South Africa just to shake his hand.

Mr Mandela had taken the day off from affairs of state to concentrate on one of the biggest issues of his life. He had long decided that part of his legacy must be his contribution to help the most deprived children of the world. To make it happen he needed to raise a great deal of money, and this day was to be Fund Raising Day for the Nelson Mandela Children's Fund.

There was a wonderful vehicle at hand to support it: the Blue Train, the ultimate in luxury rail travel, was to be relaunched. And in return for hosting President Mandela and his guests on its trip to Cape Town, the organisers were assured of the maximum possible publicity for the event.

In the early morning sunshine the invited passengers began to turn up: over there was Archbishop Tutu, never one to miss an occasion, and that one was Quincy Jones. Jemima and Imran Khan were just turning up at the end of the platform and that little lady with the frizzy hair and children had to be Mia Farrow. A tall elegant woman unwound herself from the back of a Mercedes and sashayed down the platform as if it was a catwalk. There was no mistaking her: Naomi Campbell.

ANC ministers greeted rich white South African businessmen and bankers like old friends and all settled into their comfortable seats for the first glass of champagne of the day. Then all stood as the President came through, accompanied by his fiancée (he would marry her on his 80th birthday a year later), Graça Machel, widow of the former Mozambique president who was killed in an aircraft crash which many still believe was caused by the old apartheid security forces.

And so we moved out on our 1,000-mile journey. I was there with most of the others because, one way or another, we had all contributed to the children's fund and Mr Mandela still believed he could, in his charming but determined fashion, get even more out of us. The Independent Newspaper Group in South Africa, of which I was chief executive, had organised major fund-raising events and its proprietor, Sir Anthony O'Reilly, was a large personal donor to the funds.

None of us, and certainly not Mia Farrow or Ms Campbell, had the slightest inkling that this trip, and the dinner which had preceded it at the President's Pretoria residence the night before (which very few travelling on the train had been at), would be analysed in such excruciating detail in a court in The Hague 13 years later. The stars and celebrities had come to South Africa, not for that now infamous dinner and photo-shoot with Charles Taylor (definitely not aboard), but for this train ride. This was the highlight of their trip, and they had been invited specifically for it. The private dinner the previous evening, which Mr Taylor attended, was thrown in as a polite gesture for those guests, including Ms Campbell, Ms Farrow and the Khans, who were staying in the President's guest house.

We now know that Ms Campbell came aboard the Blue Train that morning still bubbling with excitement at the bizarre events of the night. Mr Taylor, it seems, like many men in her life, had taken a fancy to her at the Mandela dinner, and, presumably in the hope of taking the relationship a tad further, promised to give her diamonds. But he didn't have them to hand and had to send his thugs to Johannesburg to get some. They arrived back in the early hours, woke her up, and presented her with an unprepossessing paper packet of what Ms Campbell later described as "dirty-looking pebbles" and which Mia Farrow, who never saw them, said was one "huge" diamond. Ms Campbell clearly had expected something that glittered, and whatever amorous hopes he nurtured were dashed.

This was the tale she had related over breakfast to Ms Farrow and her agent Carole White and it was that conversation that landed all three of them in court this past week. On this slender evidence of hearsay and chit-chat between women who are now at each other's throats rests the prosecution case against one of the nastiest men of our age.

The train was not supposed to stop until we reached the sea but seeing the crowds lined up all the way along the track, Mr Mandela ordered an unscheduled halt at Kimberley, the first of many. The irony was lost on us all then, but by a strange coincidence, Kimberley is a town entirely created by diamond wealth, and the Kimberley Process Certification Scheme, the world watchdog on "blood diamonds", is named after it. The stones that Ms Campbell had in her handbag at that moment were nothing in comparison to the enormous gemstones which were once found in the dust in what is today the main street. Blood flowed over those too.

Mr Mandela insisted that everyone must get off and join him in greeting the throngs at the station. He was brilliant on these occasions, warm, self-deprecating and witty, and soon had the crowd roaring with laughter. Then, in his typically mischievous way, he propelled a reluctant Ms Campbell to the front. "I know you have not come just to see an old jailbird like me," he joked to the crowd. "You have really come to see the most beautiful woman in the world. It's Naomi Campbell you've turned out for." Few people in the crowd had the slightest idea who or what Naomi Campbell was, but they shouted their approval anyway. It was Jemima Khan's turn at the next stop.

At what stage of the journey Ms Campbell decided to get rid of her pebbles no one now remembers clearly, but Carole White reckons it was after lunch, which probably puts it about the middle of the Free State. And this is where the tale turns more serious.

Jeremy Ractliffe, director of the Children's Fund, was the life and soul of the Children's Fund, the man who followed up through every door opened by Mr Mandela, and who was as motivated as his patron at raising money. And he was good at it – there were few people on the train who hadn't felt his long arm. Ms Campbell, who knew him slightly, sought him out and offered the diamonds to him on the basis that it was illegal for her to have them, they might help the children – and she didn't want them anyway.

Mr Ractliffe didn't want them either. If it was illegal for her, it was equally illegal for him. And being a South African, he would have known a great deal more about Charles Taylor and the suspected source of the diamonds than she did. Oddly, he took them home, put them in his safe, and never told anyone about them until last week when they became hotter than the stone in the film Blood Diamond. He now faces a police investigation, as well as questions from his fellow trustees at the fund. And the blast of publicity, following several other incidents, will make it more difficult for the various Mandela funds in the future. One advantage of old age is that Mr Mandela is probably blissfully unaware of the whole controversy.

The three women who travelled on the train that day and who have testified in the past week have all, in very different ways, made poor witnesses for the prosecution. If Mr Taylor gets off because of them, the setback to the war on blood diamonds, and the atrocities associated with it, will be too awful to contemplate.