The supermodel, the dictator and the blood diamond at midnight

Naomi Campbell, Mia Farrow and Nelson Mandela in a tale of midnight assignations and blood diamonds delivered at bedroom doorways. The latest fantastical Hollywood screenplay? No, it's the latest twist in the bid to bring the west African dictator Charles Taylor to justice for war crimes.

Prosecutors last night asked the UN-backed court trying Mr Taylor to subpoena the British supermodel, as they seek to prove that the former Liberian president personally handled blood diamonds collected from Sierra Leonean rebels in return for arming them during a decade-long civil war.

"There is evidence that Ms Campbell was given rough diamonds by the accused in September 1997," prosecutor Brenda Hollis said in papers filed with the Special Court for Sierra Leone.

That September, Ms Campbell, Mr Taylor and Ms Farrow were all guests of the then-South African president, Nelson Mandela, at a charity dinner hosted at his Cape Town home.

According to Ms Farrow, the British model came down the next morning and regaled her breakfast companions with an "unforgettable story" about being woken up by aides to the Liberian leader who were delivering a glittering gift from their boss.

"You don't forget when a girlfriend tells you that she was given a huge diamond in the middle of the night," the American actress told ABC News.

When the US network tried to question Ms Campbell about the incident, the model, who has widely acknowledged anger-management issues, punched the camera and stormed off.

Mr Taylor – on trial in The Hague for murder, rape, mutilation and sexual slavery during wars in Liberia and Sierra Leone that killed more than a quarter of a million – has dismissed the reports as "totally, totally inaccurate".

However, the prosecution said that in recent days, Carole White, the model's agent at the time of the Cape Town dinner party, had corroborated Ms Farrow's account. "She personally heard Mr Taylor say that he wanted to give diamonds to Ms Campbell and she personally saw the diamonds delivered," Ms Hollis said in her motion.

According to the prosecution, the incident rebuts Mr Taylor's testimony that he was never in possession of blood diamonds. "I was supposed to be such a scumbag that people were bringing me diamonds in nothing but a mayonnaise jar? How much more can you demonise me?" the Liberian strongman scornfully told the court earlier in the trial.

Prosecutors say they were forced to seek to subpoena Ms Campbell after her repeated refusals to be formally interviewed about the incident, either on the telephone or in person.

In an appearance on Oprah Winfrey's sofa earlier this month, Ms Campbell shed some light on her motives to stay away from the Hague courtroom. "I don't want to be involved in this man's case – he has done some terrible things and I don't want to put my family in danger," she told the queen of American daytime television.

Ms Campbell's agent had no immediate comment to make last night.

Judges in The Hague must now decide whether to grant the subpoena request. If they do, and Ms Campbell still refuses to appear, the court could then seek the assistance of the British government to get her to the witness stand, court officials said.

Mr Taylor, the first African leader to stand trial for war crimes, is facing 11 charges including murder, rape, mutilation and sexual slavery during wars in Liberia and Sierra Leone that killed more than a quarter of a million.

His defence is expected to wrap up this summer. After that, prosecutors want permission to reopen their case, so they can call Mses Campbell, Farrow and White to the stand.