This thread is fantasy. Heathrow isn't going to move. It's not in the best place but that's the story of the entire South East.
The Tories are looking at cutting 10% from parts of public spending, and the country is damn near broke. People are angered at the thought of the already massive expense and disruption of a third runway and that is a mere fraction of concreting over something the size of Heathrow elsewhere in the already overcrowded and overpriced London area.
Imagine the scenario : "Hello, we want to build a brand new airport, bigger than any other in the country BY FAR in your nice leafy home counties area." WHAT???
IT'S NOT GOING TO HAPPEN!