The UK's Airports Commission has rejected a plan for a new hub airport in the Thames Estuary, leaving just London Gatwick and Heathrow in the running for future expansion.
Airports Commission chair Howard Davies says that after detailed study, the body has concluded that the proposal for a four-runway hub to the east of London had "substantial disadvantages that collectively outweigh its potential benefits".
He says: "While we recognise the need for a hub airport, we believe this should be a part of an effective system of competing airports to meet the needs of a widely spread and diverse market like London's."
The Commission chief adds that there are "serious doubts" about the delivery and operation of a large hub in Kent and says overcoming the environmental concerns "may prove impossible". The cost of the plan was also a factor, Davies says, with even the "least ambitious version" of the scheme costing between £70 billion ($116 billion) and £90 billion.
The Commission's decision to drop the Thames Estuary proposal leaves three shortlisted expansion options on the table: a third runway at Heathrow, an extension of one of Heathrow's existing runways and a second runway at Gatwick.
John Holland-Kaye, chief executive of Heathrow, which supports the third runway proposal, responds by saying: “Heathrow is now the only hub left in the race. We would like to work with the Mayor [of London, Boris Johnson] to deliver Heathrow expansion in a way that benefits the whole country while reducing noise impacts for local people compared to today."
Writing in The Telegraph, Johnson has described the Commission's decision as "mystifying and depressing", adding: "We need the scale and ambition to compete, and Heathrow is no answer."
Gatwick chief executive Stewart Wingate, meanwhile, says the decision was an "important juncture in the aviation debate" and that the Sussex airport has the "strongest case" for expansion.
"It is the only option left on the table that can be delivered with more certainty than either of the Heathrow options, and it can be delivered without the significant environmental impacts expansion at Heathrow would inflict on London. It can be delivered faster than any other option, and at low cost and low risk," he says.
Jock Lowe from the Heathrow Hub scheme says he hopes that Johnson will now back the extension of Heathrow's runway after the London Mayor's favoured scheme for an Estuary gateway was rejected.
"We can deliver the new airport capacity required cost effectively," says Lowe. "And by extending the existing runway, we bring no new communities in West London into the noise footprint, so ours is now the most politically realistic plan still being considered by Airports Commission. We again respectfully ask Mr Johnson to get behind Heathrow Hub in delivering this important project for London and for the nation."
The Commission plans to publish an appraisal of the three remaining options for public consultation in the autumn, but a decision by the UK government as to which proposal to take forward will not be taken until after the general election in 2015.