A map, created for a 2019 public consultation, shows how the airport could be laid out post-expansion. The third runway, labelled as ‘1’, would sit north-west of Heathrow’s current infrastructure, towards Colnbrook and Harmondsworth.

The cost of building a third runway at Heathrow Airport is estimated to be at least £14 billion and would be paid for by the airport owners, the BBC reported. However, the total cost could be much higher due to the cost of the associated road and rail infrastructure.

The third runway is part of its drive to lift the U.K. economy out of a long period of stagnation, Treasury chief Rachel Reeves said in a speech on Wednesday.

What could a third runway at Heathrow mean for tourism and the climate? Whatever the outcome, it’s still a long way away from happening.