The government has selected Heathrow Airport Ltd's £33bn plan for a third runway, set to be operational by 2035. The chosen scheme involves a 2.2-mile north-western runway crossing the M25 motorway, which will require relocating and rebuilding a section of the motorway at an estimated cost of £1.5bn.
Transport Secretary Heidi Alexander said the proposal was the "most credible and deliverable option," ahead of a rival plan by the Arora Group. The decision allows swift progress toward full planning permission by 2029, provided the runway meets the government's four tests on environmental, economic, noise, and air quality considerations.
The Arora Group's alternative, a shorter 1.7-mile runway to the east costing £23bn and not requiring M25 relocation, was rejected. However, its chairman Surinder Arora said the company would continue to pursue building the runway, noting the option for a different promoter remains possible.
The expansion could add up to 760 more flights daily, increasing capacity to 756,000 flights and 150 million passengers annually. The runway itself costs £21bn, with an additional £12bn for infrastructure like satellite terminals, and a further £15bn in airport improvements—all privately financed.
Environmental groups criticised the plan. Tony Bosworth of Friends of the Earth called it incompatible with climate targets, likening it to "bolting an airport the size of Gatwick on to Heathrow." The government insists it will consult the Climate Change Committee to ensure consistency with net zero obligations.
