Following detailed further study into the feasibility of building the ambitious gateway, championed by London Mayor, Boris Johnson, and dubbed "Boris Island" - the commission has concluded the proposal on the Isle of Grain in Kent has "substantial disadvantages that collectively outweigh its potential benefits".
The commission has already shortlisted two options at Heathrow Airport, one to build a new runway, and the second to extend an existing runway, while an option has also been shortlisted to build a second runway at Gatwick Airport.
Airports Commission chair, Sir Howard Davies, explains: “We are not persuaded that a very large airport in the Thames estuary is the right answer to London’s and the UK’s connectivity needs.
“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.
“There are serious doubts about the delivery and operation of a very large hub airport in the estuary. The economic disruption would be huge and there are environmental hurdles, which it may prove impossible, or very time-consuming to surmount.
“Even the least ambitious version of the scheme would cost £70 to £90 billion with much greater public expenditure involved than in other options – probably some £30 to £60 billion in total.
“There will be those who argue that the commission lacks ambition and imagination. We are ambitious for the right solution.
“The need for additional capacity is urgent. We need to focus on solutions, which are deliverable, affordable, and set the right balance for the future of aviation in the UK.
“The commission received and developed a substantial body of evidence that it considered very carefully over a number of months before reaching this decision.”
Alongside today’s announcement the commission has published a paper in which it sets out in more detail the reasoning behind its decision, and will continue its appraisal of the three shortlisted proposals for additional capacity and publish the appraisal for public consultation in the autumn.
The commission will then give its recommendations to the government after next summer’s general election.
London Mayor Boris Johnson says his proposal for an island airport in the Thames estuary is not dead, despite the commission rejecting the idea, and calls the move short-sighted, and explains plans to expand either Gatwick or Heathrow would fail.
Johnson adds: "In one myopic stroke, the Airports Commission has set the debate back by half a century and consigned their work to the long list of vertically filed reports on aviation expansion that are gathering dust on a shelf in Whitehall.
"Gatwick is not a long-term solution and Sir Howard Davies must explain to the people of London how he can possibly envisage that an expansion of Heathrow, which would create unbelievable levels of noise, blight and pollution, is a better idea than a new airport to the east of London that he himself admits is visionary, and which would create the jobs and growth this country needs to remain competitive."
Sir Howard Davies also told the Mayor that there will need to be a decision by the government on a second additional runway by 2020.
Responding to the decision, Gatwick chief executive, Stewart Wingate, says it is an important juncture in the aviation debate because Britain’s choice is now clear, and adds: "Expand Gatwick and support genuine competition, lower fares and greater choice for passengers or expand Heathrow and return to the stale monopoly of the past and watch the cost of going on holiday, travelling for business and exporting goods and service go up.
“We believe Gatwick has the strongest case. 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 continues that expanding Gatwick will ensure the UK is served by two successful world-class airports, and “liberate” hub capacity at Heathrow and open up the opportunities for affordable long-haul travel to emerging markets for the benefit of everyone.
Heathrow CEO, John Holland-Kaye, comments: "We have always agreed with the Mayor that Britain needs a successful hub airport to compete in the global race for jobs and growth. Heathrow is now the only hub left in the race.
"We would like to work with the Mayor to deliver Heathrow expansion in a way that benefits the whole country while reducing noise impacts for local people compared to today.”