Plans to expand London's other airports are already further along than Heathrow's and have in the past been viewed as an alternative to a third Heathrow runway. Work is set to start this year to expand capacity at Stansted's terminal. The government is due to make a decision on Gatwick airport by 27 February.

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.

The UK’s busiest airport will get a third runway and a new terminal after confirmation by Chancellor Rachel Reeves today. Airport bosses have been pushing for the expansion for years, arguing that Heathrow’s capacity is full. They said the £14 billion expansion is needed to add 260,000 flights.