Freshfields is representing Bahrain and Eversheds is acting for Qatar in a dispute over the boundaries between the two Middle Eastern countries.
However, the case, which is due to be heard before the World Court in the next few weeks, has been delayed by allegations of forgery of documents.
Freshfields senior associate Robert Volterra, who recently transferred from the firm's Paris office to set up a public international law (PIL) practice in London, claims that Eversheds' client presented 82 “crude forgeries” of documents.
“We have spent a year and a half using the most advanced forensic techniques to discover the authenticity of the documents,” says Volterra.
Historians and hand-writing experts have been employed by the firm. In some cases it is suggested mistakes have been easy to spot.
Volterra says “There were unbelievable things like a Queen Elizabeth stamp appearing on documents that were supposed to be from the nineteenth century. It's been pretty eyebrow raising.”
On the Eversheds side well-known PIL lawyer Rod Bundy is in charge of the case.
He disputes the suggestion that some of the Qatar documents were fakes.
“Qatar does not recognise that any documents are forged. Experts have differing opinions on their authenticity, so Qatar has said it will simply disregard those documents.”
He adds: “As a general rule of thumb I do not think lawyers should comment on cases still pending. Both parties will make submissions to the court at the end of May.”
Bundy is also representing Indonesia in a dispute with Malaysia over two small islands.
The action is the first time countries in the Asean region have taken each other to court, usually preferring to settle disputes “in the family”.
Freshfields has become only the fifth firm to offer a London based PIL service which will provide clients with both contentious and non-contentious advice.