Ambitious plans for a four-runway Thames Estuary hub airport have officially been rejected today in a move that has delighted campaigners.

The government-appointed Davies Commission, which is examining options to increase aviation capacity in the south east, has dismissed the scheme planned for the Isle of Grain.

Effectively drawing a line under the "Boris Island" idea, the announcement has been welcomed by opponents in Kent and Medway - but has been slammed by London mayor Boris Johnson, who vowed to continue pushing for an estuary airport.

Sir Howard Davies, who is leading the investigation, ruled there were serious doubts about an estuary airport, arguing the scheme would be too expensive - leaving the taxpayer with a bill of up to £60billion - and face environmental hurdles that might be impossible to overcome.

It means the commission has been left with three options for airport expansion in the region.

There are two additional runway plans for Heathrow and one for Gatwick. The latter is likely to provoke opposition from campaigners in west Kent, where there are long-standing concerns over noise from flights.

Announcing his decision, Sir Howard said: "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.

"The economic disruption would be huge and there are environmental hurdles which it may prove impossible, or very time-consuming to surmount..." - Sir Howard Davies

"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 £60billion 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.

"The commission will now continue its appraisal of the three shortlisted proposals for additional capacity and will publish the appraisal for public consultation in the autumn."

It last year short-listed the Heathrow and Gatwick options - but said it would examine the estuary option.

Several reports have since been published showing the possible environmental cost, with council leaders, MPs, residents and environmental campaign groups all voicing their opposition to a scheme they believed would be too costly and damaging to the area.

"The cost to the taxpayer was never fully explained and it would have resulted in the mass destruction of habitat and wildlife that could never be replaced..." - Medway Council leader Rodney Chambers

However, there has been support from some businesses in both Medway and elsewhere in Kent.

The announcement was met with delight by Medway Council leader Cllr Rodney Chambers after a six-year fight.

He said: "I am pleased our campaign to stop the Thames Estuary Airport has been successful.

"We have said all along that it should never have even been considered. The cost to the taxpayer was never fully explained and it would have resulted in the mass destruction of habitat and wildlife that could never be replaced.

"This scheme has been a distraction we could have done without as we worked on our existing regeneration plans to bring new jobs and homes to Medway.

"We have known from the start that this plan was wrong, but still had to fight until the end to ensure it never got off the ground.

"This has never been about 'nimbyism'; this has been about fighting for what is right for Medway and the environment."

Cllr Vince Maple, leader of the Labour group on Medway Council, said: "Today's announcement brings closure to so many Medway residents who have been concerned about these ludicrous proposals.

"I have repeatedly said an estuary airport would be bad for the environment, bad for Medway and bad for UK PLC and it is pleasing to see the Davies Commission agreeing with that position."

Cllr Geoff Juby, leader of the Liberal Democrat group on Medway Council, said: "I am delighted that someone has at least seen sense, and I trust that this project is now dead for good even if Boris Johnson should succeed in becoming Prime Minister."

Gillingham and Rainham MP Rehman Chishti said: "The independent commission has listened to what we have been saying for many years; that it would be totally impractical, costly and would destroy important environmental sites.

"Local residents can now get on with their lives without the uncertainty that their local environment and quality of life would have been destroyed by this bizarre proposal."

Sheppey and Sittingbourne MP Gordon Henderson said: "I'm absolutely delighted, but not surprised.

"I've long believed it was a non-starter and I've made that known publicly on a number of occasions.

"It's good news for Sheppey because a Thames Estuary airport would've absolutely destroyed the quality of life for people living on the Island.

"Building an airport in this area would lead to environmental destruction on an unprecedented scale..." - Kent Wildlife Trust

"I believe the number of jobs the airport would've created has been overstated. All it would've done was brought in people from outside the area to work at the airport, increasing the amount of traffic on our roads and putting pressure on developers to build even more houses."

Swale council leader Cllr Andrew Bowles said: "I'm very pleased. It's a victory for the environment and a victory for the people of Kent.

"I hope Boris concentrates on something else now such as becoming an MP.

"If he continues fighting for an estuary airport, we shall continue to oppose it with undiminished vigour."

And Kent Wildlife Trust welcomed the rejection of the estuary airport proposals.

Thames gateway officer Greg Hitchcock, from the trust, said: "Building an airport in this area would lead to environmental destruction on an unprecedented scale.

"The damage caused by these proposals is totally unjustifiable, both morally and economically. We are glad the Airports Commission has ignored the political posturing and applied some common sense."

Reacting angrily to the rejection of an estuary airport, Mr Johnson said it "remains the only credible solution" and vowed to continue the fight.

He said the remaining options "will fail to provide the global connectivity that can only come from a large, four-runway hub airport".

"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..." - Boris Johnson

The mayor said he "remains convinced a future government will return to plans for a hub airport on a site to the east of London, and any future recommendation made by the Davies Commission will be irrelevant".

Mr Johnson said: "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 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.

"It remains the only credible solution, any process that fails to include it renders itself pretty much irrelevant, and I'm absolutely certain that it is the option that will eventually be chosen."

The ambitious scheme for an estuary airport's fate was sealed after suffering a serious setback in July.

Three reports were published suggesting the costs could spiral by billions of pounds, taking into account compensation to the owners of Heathrow, the need for new roads and other infrastructure and removing SS Montgomery, a sunken wreck with explosives.

Gatwick Airport chief executive Stewart Wingate said the commission's decision was the right one. The commission is due to make its final report to MPs next summer after public consultation.Stories you might have missedHealth trust in special measures amid patient safety fearsMurderer brandishes 2ft metal pole in drunken rantHealth and safety concerns keep school closed on first dayLanterns released in memory of tragic biker killed in crash

He said: "This is an important juncture in the aviation debate because now Britain's choice is clear; 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."