A third runway could allow airport to expand to 150 million passengers a year, nearly double the current scale

The new 3.2km runway would require a diverting the M25, building a new road tunnel under the airport and widening the motorway between junctions 14-15. Thomas Woldbye, the CEO at Heathrow said that the new M25, 100m west of the current one, would be ‘wider and it will be safer and it will have more capacity’.

London's Heathrow Airport on Friday unveiled a £49-billion ($65 billion) expansion plan, including the costs of building a long-awaited third runway, approved by the UK government after years of legal wrangling.