The protesters gathered on Friday at a site which, under expansion proposals, would be used to build a new runway.

About 100 people opposed to the scheme were expected to set up camp during the evening on common land in the Essex village of Molehill Green.

They have vowed to remain on the land until the expansion plans are dropped.

Frances Duncan, 57, of the protest group Runway Noway, said if the new runway went ahead it would have a devastating impact on the environment.

Expecting opposition

She claimed about 100 homes in Molehill Green would be lost along with an ancient monument and a wet woodland of special scientific interest.

She added the expansion would also add to pollution in the area.

"They say it will create jobs but we have full employment in the area," she said. "We do not need to concrete over the south east."

Ms Duncan said the protesters were expecting police to try to stop them setting up the camp but said they would not give up on their aim.

Airport owners, the British Airport Authority, have begun offering compensation packages to home owners whose properties would be affected by the scheme.

Last December's aviation White Paper supported a new Stansted runway - a project which may be ready by 2011.