A major political row is brewing after an eagerly-anticipated independent report recommended that Heathrow airport should get a third runway.
Sir Howard Davies' Airport Commission announcing an expansion of Heathrow is the "best answer" to solve airport congestion will cause a major headache at the heart of Government.
London Mayor Boris Johnson this morning claimed the £19 billion upgrade would be a "catastrophe" and will "never be built", while Labour pledged "swift" backing.
The report raises environmental concerns over expanding Heathrow but Sir Howard dismissed any suggestions of a political "fudge".
While an alternative increase of flights at Gatwick is "plausible", he told journalists Heathrow expansion was a "clear recommendation" - giving ministers little room to wriggle free.
If Heathrow gets the go-ahead, it would build the first new runway in the South East since the 1940s.
Sir Howard's recommendations are not binding on the Government, yet David Cameron's response is fraught with problems as the Prime Minister pledged in 2009: "No ifs, no buts, there'll be no third runway at Heathrow."
The report says: "The Commission has unanimously concluded that the proposal for a new northwest runway at Heathrow Airport, combined with a significant package of measures to address its environmental and community impacts, presents the strongest case and offers the greatest strategic and economic benefits."
The Davies report demands no fourth runway, a ban on all scheduled night flights from 11.30pm to 6.00am and a cap on noise levels among a series of mitigation measures.
But he underlines Heathrow can take more long-haul flights which are "crucial to the country’s prosperity" and help boost under-used UK regional airports - making the Government's decision all the more tricky given its emphasis on the economy and closing the north-south divide.
Sir Howard said:
"At the end of this extensive work programme our conclusions are clear and unanimous: the best answer is to expand Heathrow’s capacity through a new northwest runway.
"Heathrow is best-placed to provide the type of capacity which is most urgently required: long haul destinations to new markets. It provides the greatest benefits for business passengers, freight operators and the broader economy."
Heathrow has been chosen as the best option for expansion over Gatwick
At a press conference this morning, Sir Howard said after the report was two-and-a-half years in the making there was "only so long you can hide in the long grass".
Critics said his analysis was only commissioned so the Conservatives could kick the issue beyond this year's election.
His report says the proposed expansion at Heathrow will add around 40 new destinations from the airport and create more than 70,000 new jobs by 2050.
But residents of Heathrow's neighbouring villages are furious, with hundreds of homes earmarked for demolition if it gets the green light.
Shadow Transport Secretary Michael Dugher has made clear Labour could swiftly back Heathrow, so long as it "tests" including over the impact on the environment.
"We must not let politics get in the way of good business – there is too much at stake. This issue has been kicked into the long grass too many times," he said.
The report found 60% of the benefit of Heathrow goes to areas outside London, meaning Mr Cameron risks being accused of putting party before country if he doesn't back it.
Options considered included adding a third runway at Heathrow, lengthening an existing runway at Heathrow, and a new runway at Gatwick.
A brand new airport on the Thames estuary - dubbed Boris Island - was dismissed early on as "unfeasibly expensive, highly problematic in environmental terms and would be hugely disruptive for many businesses and communities".
Cabinet ministers Theresa May, Phillip Hammond, Greg Hands, Justine Greening and Theresa Villiers are opposed to Heathrow's expansion because of constituents living under flightpaths, as are Mr Johnson and Richmond Park MP Zac Goldsmith.
Some reports this morning suggested Mr Cameron has already decided to expand Gatwick despite the commission’s recommendation.
Senior Tory sources told The Sun it was to avoid a party split, and a number of damaging Cabinet resignations.
The report says that the Heathrow expansion means that by 2030 more than 550,000 people will be affected by a level of noise that is "irritating", rising to between 570,000 and 640,000 by 2050.
Mr Johnson was the first to criticise the decision, signalling the proposal should be binned.
Both he and Zac Goldsmith, who is poised to stand as Mr Johnson's mayoral successor, have been among two the most vociferous opponents of Heathrow expansion.
Mr Johnson likened plans to build a new runway to a scheme from Maoist China.
"I don't think this is going to happen, this is the sort of thing you could possibly have got away with in China in the 1950s but the impact on London, the impact on the city, the environmental cost, the whole human rights [and] legal challenges that will inevitably ensue will be so great that I don't think it's deliverable," Mr Johnson told Radio 4's Today programme.
Mr Goldsmith, who has said he would call a by-election should the Government backed the Commission, told BBC News it was "not the end of the road” in the decision over a new runway for the south-east, and bemoaned the continued “prevarication” the verdict will provide in the coming months.
“It’s a very disappointing process and I think Sir Howard Davies has missed an opportunity and the effect is we are going have delay, we are going to have prevarication … fudge and so on, and a lot of protest,” he said.
MPs from across the political divide gathered in Westminster to demonstrate their opposition.
John Holland-Kaye, chief executive of Heathrow Airport, said: "This debate has never been about a runway, it's been about the future we want for Britain.
"Expanding Heathrow will keep Britain as one of the world's great trading nations, right at the heart of the global economy."
He added: "Our new plans have been designed around the needs of local communities and will meet carbon, air quality and noise targets, and provides the greatest benefit to the UK's connectivity and its long term economic growth.
"We will create the world's best connected, most efficient and most environmentally responsible hub airport at the heart of an integrated transport system. The Commission has backed a positive and ambitious vision for Britain. We will now work with Government to deliver it."
Gatwick Airport CEO Stewart Wingate said: "The Commission's report makes clear that expansion at Gatwick is deliverable.
"It is for the Commission to make a recommendation but it is of course for the Government to decide. So we now enter the most important stage of the process.
"We are confident that when the Government makes that decision they will choose Gatwick as the only deliverable option. For instance, this report highlights the very significant environmental challenges at Heathrow such as air quality and noise impact."