Campaigners opposed to expansion at Gatwick Airport are threatening to form blockades and set up 24-hour protest camps.

Should work on a second runway start, peaceful rallies are expected to be abandoned for more direct action.

This week, anti-airport groups from across the South-East held a conference in London with Rising Tide, a grassroots anti global-warming group which seeks to dismantle the oil trade.

The meeting was organised by Hacan ClearSkies, an anti-Heathrow pressure group but residents' groups from Gatwick and Stansted also attended.

Future action might include go-slow convoys and roadblocks near the airports. There are also likely to be protest camps in tunnels, modelled on the opposition to Manchester's second runway in the 1990s.

Anti Gatwick expansion campaigner Brendan Sewell said today they stood shoulder to shoulder with their counterparts at Heathrow and Stansted.

He said: "As a group, the Gatwick Area Conservation Campaign will not encourage people to take direct action. We are responsible and law abiding.

"On the other hand, we know that a lot of people have strong feelings and therefore we will have sympathy with people if they needed to take some sort of direct action."

In June this year, more protestors, led by GACC, staged a mock confrontation with a bulldozer during a demonstration.

More than 500 people turned up to the rally, which saw the bulldozer 'held at bay' at the entrance to a wood at a point known as Edolphs Copse.

The government is due to release plans for new runways by the end of this year.

Protesters are upset that airport expansion will lead to increased noise levels, loss of land for housing and agriculture and the demolition of historic areas.

But supporters of the schemes say the UK economy will suffer if airports do not expand.