Brendon Sewill, chairman of the Gatwick Area Conservation Campaign, said: 'We have always been totally opposed to a new runway on environmental grounds, and have had massive support from across Surrey, Sussex and west Kent.
"We have been supported by all the local MPs and all the county, district and parish councils in a wide area. If necessary, we will resume the battle."
More top news
The high of 35C was recorded on a Bakerloo line train between Piccadilly Circus and Oxford Circus at 2pm.
Weather forecasters say temperatures could reach 35C, beating the previous record of 34.6C in the scorching summer of 1976.
After years of political manoeuvring over the future expansion of Heathrow Airport, there has been an important development this lunchtime.