OPPONENTS of proposals to build a new runway at Gatwick have warned they will take legal action if the government gives the airport permission to expand.

The Sussex branch of the Campaign to Protect Rural England (CPRE) is among 18 action groups across Surrey and Sussex which have united to write to Prime Minister Theresa May.

Mrs May is widely tipped to make a decision on whether to back a new runway at Heathrow or Gatwick this week.

Chairwoman of Communities Against Gatwick Noise and Emissions Sally Pavey said: "Any expansion of Gatwick would be legally scrutinised with a view to protecting the heritage and areas of outstanding natural beauty that surround Gatwick in a 30 mile radius.”

The letter said: “We do not believe that the destruction of wildlife, our tranquillity, our dark night skies and clean air can be justified by the expansion of Gatwick.

"Gatwick expansion is not just about a runway. It comes with huge baggage that would destroy the very landscapes we seek to protect and promote for future generations.

"We have to be smart about future growth and prosperity."

The Davies Commission recommended in July last year that a third runway should be built at Heathrow.

Other shortlisted options are extending the airport's existing northern runway or building a second runway at Gatwick.

The decision has been repeatedly delayed due to its political sensitivity.

In preparation for a possible Heathrow victory, it has been reported that Gatwick has been offered a consolation prize.

Ministers are said to have asked Gatwick for a list of compromise options should it not get the go-ahead for a new runway.

Sources in a national newspaper yesterday claimed that transport secretary Chris Grayling, in private meetings, pressed the airport on what ministers could do to help if it lost out.

A source is quoted as saying: “Gatwick were asked to give some sort of compromise: ‘What would you take, other than a runway, that would smooth this over?"

One option was mooted be a package of rail and road improvements.