BAA, the operator of London’s largest airport, Heathrow, will return to the High Court today to seek “the mother of all injunctions” to prevent thousands of people affiliated to environmental organisations from attending the Camp for Climate Action at the airport from 14 to 21 August.

The company says it wants to “protect the airport and the safety of passengers and staff against the planned direct action by environmental activists”.

But environmental groups accuse BAA of “corporate bullying” designed to shut down peaceful protest.

“They are trying to bully over 5 million people who are critical of their plans to massively increase their output of greenhouse gases,” said Joss Garman of the anti-aviation group Plane Stupid, one of the groups named in the BAA court action.

The injunction application, which is one of the most draconian ever sought in the UK, seeks to impose bans on people travelling on the London Underground, on mainline trains and on motorways. John Stewart, the chairman of the Heathrow anti-noise and anti-expansion organisation Hacan, said: “This is the mother of all injunctions.

In court yesterday, BAA denied it was trying to stop 5 million members of the National Trust and other groups going to Heathrow to demonstrate against climate change, but said it still wanted to ban the Camp for Climate Action,

However, amid scenes of near farce at the Royal Courts of Justice, Justice Caroline Swift, asked BAA’s lawyer to clarify the terms of the injunction he was seeking, stating: “I have to know what I am being asked to do.”