Airport operator BAA is heading to court to seek a wide-ranging injunction to prevent a major climate change protest taking place at Heathrow.
BAA owns seven airports in the UK
Thousands of campaigners, opposed to the airport's expansion, are expected to set up a ring of camps around Heathrow between 14 and 21 August.
BAA, which runs Heathrow, wants to ban 15 groups from taking part in the Camp for Climate Action protest.
The National Trust and the RSPB are among those facing the proposed ban.
They have been earmarked because they are affiliated to Airport Watch, an umbrella organisation which unites green bodies and community groups opposed to the expansion of the aviation industry.
Demonstrators are threatening what they call a week of "high impact" direct action.
Organisers hope as many as 5,000 people will take part, spending a week in tents outside the UK's busiest airport.
'Mother of all injunctions'
BAA insists it is seeking the ruling "to protect the operation of the airport and the safety of passengers".
A spokesman for BAA said 200,000 people a day passed through the airport during the busy August period, adding: "It is these people who would suffer as a result of any unlawful or irresponsible behaviour.
"We respect people's right to protest within the bounds of the law and airport bylaws, and we would invite protesters to similarly respect the rights of passengers travelling through Heathrow."
But the protesters claim BAA has resorted to "legal bullying" and has gone over the top by trying to extend the ban to people using the road and rail network near the west London airport.
London Mayor Ken Livingstone has accused BAA bosses of being "out of their skull" and claimed the injunction application has increased the likelihood of hardcore protesters invading the camp.
Hacan, the Heathrow anti-noise and anti-expansion organisation, is one of the groups named in BAA's court action.
Its chairman John Stewart said what was being sought was the "mother of all injunctions".
"This is a cut-and-dried case of corporate bullying designed to shut down peaceful protest," he said.
Friends of the Earth is also facing the ban and its lawyer Gita Parihar said: "This is an unnecessary and unworkable request by Heathrow Airport and we are confident it will be thrown out of court.
"We believe people have the right to protest peacefully about issues which concern them such as climate change."
Civil rights group Liberty said the injunction was an example of a "dangerous and undemocratic trend" by large companies to seek to limit the right to protest.
The case is expected to be heard at the High Court on Wednesday.