London's High Court will on Wednesday hear allegations of dirty tricks in the biggest class action ever brought before the British courts.
It arises from the dumping of toxic waste three years ago in Ivory Coast's largest city, Abidjan.
In the aftermath, up to 100,000 people fell sick and 16 died.
The waste belonged to a multi-national oil trading company, Trafigura. In the wake of the incident, 30,000 Abidjanis are suing them for damages.
Before the case can start, lawyers for the BBC and other media organisations are asking for certain evidence to be made public.
This deals with accusations that Trafigura's lawyers have been implicated in attempts made by Trafigura in Abidjan to persuade key witnesses to change their statements.
The law firm representing the Abidjanis, Leigh Day and Co, allege a dirty tricks operation by Trafigura agents in Abidjan.
In March this year, pending a full hearing of those allegations, the High Court issued an injunction forbidding Trafigura representatives - including leading London law firm Macfarlanes - from contacting the claimants.
'Questioned by lawyers'
One of them, a tiler called Bou N'Dja, who had never left Ivory Coast, claims he was taken on an all-expenses-paid trip to Morocco. In a signed statement he says:
"I wanted to travel and to meet Trafigura's executives. I wanted to know why they had dumped the waste and what they wanted from me. I was curious, but most of all, I wanted to travel. I had never been on a plane..."
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He alleges that when he got to the Sheraton Hotel in Casablanca he was interviewed by lawyers for Trafigura for two days who subjected him to detailed questioning about his evidence.
Trafigura and Macfarlanes are denying any wrongdoing.
For two years, Newsnight has been investigating Trafigura's claim that the waste dumped on the streets of Abidjan was not harmful.
In Wednesday's edition of Newsnight, the programme will reveal just how toxic it is, based on tests carried out by officials in Amsterdam where Trafigura first tried to offload the waste.
John Hoskins a fellow with the Royal Society of Chemistry told Newsnight:
"If you dropped this in Trafalgar Square, you would have people being sick for several miles around, and that would involve millions of people. You'd see the effects out to the M25 ring."
In Abidjan, the outcome of the court case is keenly awaited.
Dr Jean Louis Louya treated some of the victims in the weeks following the dumping. He says many are still suffering.
"People came for consultations and they all had the same symptoms, the same problems affecting the ear, nose and throat area... still today people are sick."