The Government decision to allow expansion at Stansted is to come under a challenge in the High Court today.
The Stop Stansted Expansion group is looking to overturn the decision to allow expansion, which would allow another 10 million people to fly through the airport each year.
The group claims ministers have failed to take into account the environmental impact of the proposals.
SSE chairman Peter Sanders said he had no choice to mount a legal challenge as the government has taken the decision based on economic issues and not environmental.
The case is expected to last three days.