A second runway for Gatwick could be back on the agenda after yesterday's shock High Court defeat for the Government.

But campaigners against the plan say there's still a long way to go before Gatwick can be included in the Government's consultation document for the future of airports in the South East.

Yesterday a judge agreed with Kent and Medway councils that Transport Secretary Alistair Darling's decision to rule Gatwick out in the consultation exercise was "irrational and unfair".

The Government's consultation procedures were left in disarray when Mr Justice Maurice Kay indicated the Transport Secretary must think again and ensure Gatwick is an option.

But Brendon Sewill, of the Gatwick Area Conservation Campaign, said: "We don't know whether the Government is going to appeal. It may well do so because it is totally going to upset its timetable for airport development.

"The decision will cause a huge amount of blight and anxiety, not only around Gatwick but around all the places proposed for airports because it will be delayed.

"The judge said that to exclude Gatwick was irrational but there is no reason why the Government could not reach the same decision again. The judge did not comment on the merits of Gatwick for a second runway."

Gatwick was originally excluded from the Government's plans because of a legal agreement signed between airport operator BAA and West Sussex County Council.

The agreement prevents the building of a second runway before 2019.

But the Government agreed to include wildlife-rich Cliffe Marshes in Kent as a site for a new four-runway airport and Stansted for up to three new runways.

A BAA spokesman said: "We have often expressed surprise at Gatwick's exclusion."

Chris Redmayne, leader of Crawley Council, added: "There needs to be a robust debate about the future of air travel in the South-East which includes Gatwick and its sub-regions."

But West Sussex County Council said the judge's decision reintroduced the prospect of blight and anxiety for thousands of homeowners.

Tex Pemberton, Cabinet member for strategic environmental services, said: "Creating a second runway at Gatwick would cause appalling damage to the countryside and environment."

Sussex Enterprise chief executive Mark Froud said 87 per cent of Sussex businesses consulted said a second runway would be good for business and the local economy.

The judge ordered the Transport Secretary to pay legal costs to his opponents, unofficially estimated at not less than £100,000.