Helen Steel, 33, and Dave Morris, 44, who have an income of less than pounds 7,500 a year between them, are appealing against the ruling that they libelled McDonald's in a "factsheet" first published by London Greenpeace in the late Eighties.
A leading human rights barrister has provided the pair with detailed advice for free, although they will still represent themselves in court.
On Tuesday, Richard Rampton QC, one of the most respected libel silks in the country, will confront them once again.
The first time, despite their lack of legal training, the pairproved several important points. This time they might even win. They will argue that a multi-national corporation should not be able to sue for libel in the same way that governments and local authorities are barred from taking legal action.
The outcome of the appeal is less important for the activists, however, than the publicity it will generate. A website set up by volunteers during the first trial has been accessed more than 65 million times. The publicity surrounding the trial has given green activists a platform for disseminating embarrassing information about McDonald's far more widely than any leaflet could.
On the day the appeal hearing begins, activists will also screen a film about the case at 100 cinemas and on cable networks around the world, including 18 in Britain.
A spokesman for McDonald's Restaurants Ltd, the UK arm of the worldwide corporation, yesterday defended its decision to spend more money in court. "There were many very serious allegations aired ... at the initial trial. We welcomed the judgment when it was handed down. It is very important [it] is upheld," he said.