Controversy over Britain's plans to build a third runway at Heathrow Airport in London, already the second busiest airport in the world, escalated last month with MPs backing the airport expansion.

Prime Minister Theresa May’s government won the House of Commons vote, which saw 415 MPs vote in favor of the third runway, for a majority of 293. The significant majority in favor of the expansion indicates an instruction to the Conservatives, known as a "three-line whip," which is an order given to MPs by party leaders to vote in a certain way on a specific issue.

Interestingly, there was one high-profile figure notably absent from the Tories’ "fixed" Parliamentary vote on the project: former Foreign Secretary Boris Johnson. Johnson, who resigned from his position on Monday, had been a vocal opponent of the Heathrow development and famously vowed to “lie in front on bulldozers to stop the construction of that third runway.” He was conveniently out of the country when the vote took place.

The foreign secretary's absence meant he was spared from choosing between his cabinet job and opposing the Heathrow expansion. As it turned out, May didn’t have the headache or embarrassment of having to sack her most eminent minister.

Not all Tory MPs were as lucky. The prime minister suffered a resignation with Greg Hands, who quit his position as international trade minister through refusing to oppose the airport expansion.

Since the vote swung in favor of the expansion, objection over the £14 billion project has been snowballing, with concerns growing over the detrimental environmental affect a third runway would have on London, and how the money could be better spent.

The rise in carbon emissions is a fundamental drawback of the third runway. The government’s independent climate advisors warn that if Britain is to meet its legally binding climate change targets, carbon emissions cannot rise any further.

However, government figures forecast that if a third runway is developed at Heathrow, aviation CO2 emissions will rise by 7.3 million tons by 2030.

In a letter to Transport Secretary Chris Grayling, Lord Deben, the chair of the Committee on Climate Change (CCC), warned about the increased pressure the airport expansion would put on the U.K. to meet its climate change targets.

“Aviation emissions at 2005 levels in 2050 means other sectors must reduce emissions by more than 80%, and in many cases will likely need to reach zero,” wrote Deben. “High levels of aviation emissions in 2050 must not be planned for, since this would place an unreasonable large burden on other sectors.”

Environmental groups are already pressing for greater action in response to the decision. In the wake of what pro-expansion business groups called “a truly historical decision that will open the doors to a new era in the U.K.’s global trading relationships,” Greenpeace UK said it is ready to join the London mayor and a cross-party group of London councils in a legal challenge against the airport expansion.

“MPs who backed this climate-wrecking new runway will be harshly judged by history," said Friends of the Earth in a statement. "The evidence on the accelerating climate crisis, which is already hitting the world's most vulnerable people, is overwhelming – and expanding Heathrow will only intensify the misery.”

Ecological concerns about the airport expansion run even deeper. The Guardian columnist Owen Jones referred to the whipped up vote for a third runway, and Brexit Britain’s dash for growth, as a “Trumpian disregard for the planet.”

Airport expansion supporters cited job creation as a benefit of building the third runway. This is a short-term gain, however, according to Jones, who said the U.K. needed to devote its energy to creating long-lasting jobs in the renewable energy sector.

“By focusing on high-carbon infrastructure as a means to create jobs, we distract ourselves from exploring how we can create hundreds of thousands of skilled, well-paid, secure jobs in the renewable energy sector, as Germany has done,” he wrote.

Liberal Democrat leader Sir Vince Cable, who has been a figurehead for opposition to the project, shared Jones’ concerns over the economic damage the third runway would have on the British economy. “Heathrow expansion is expensive, will damage the environment and will end up hurting rather than helping regional economies,” he said.

Meanwhile, a recently published report by the New Economies Foundation, commissioned by the No Third Runway Coalition, confirmed the negative economic outlook. The report, titled "Flying Low: The True Cost of Heathrow’s Third Runway," found that airports outside London would experience a reduction in aviation traffic which would eventually result in their “growing more slowly” and costing airport jobs in regions across the U.K.

The report called for a more “targeted approach” to support Britain’s national air freight strategy. In addition, Paul McGuinness, Chair of the Coalition, commented: “It must be unacceptable for Heathrow to claim their proposals will be privately financed whilst seeking protections from the public purse for potential delays in construction and inaccuracies in passenger demand forecasts.”

McGuinness was stating what many already realize: that a large chunk of the bill for the environmentally destructive project will be paid for by taxpayers and passengers. The lavish £14 billion runway plan includes bridging 12 lanes of the U.K.’s busiest motorway while pumping billions of more pounds into upgrading train and railway links to what is already a highly-congested airport.

To help bankroll the expansion, raising the charges to airlines and passengers at Heathrow is already evoking criticism. Costs at Heathrow are already 40% higher than at many European airports, and further increasing passenger fees will hit many in the U.K. who already struggle to afford air travel.

Ironically, increasing charges to airlines and passengers could also result in airlines being forced to move, making it difficult to fill the airport’s new capacity.

As a result, many are voicing concern and dismay about where those billions of pounds could otherwise be spent. Ruth George, Labour MP for the High Peak, wrote in a Facebook post after the historic parliamentary vote:

“Tonight, I was a “Teller for the Noes” — counting MPs’ votes against Heathrow expansion. A third runway will increase air pollution which already kills 40,000 Londoners a year. The economic case is so poor that the company have insisted that taxpayers carry the risk, and the huge government investment will drain funds from everywhere else in the country. We need a strategy for more growth in every region, not just London.”

With the National Health Service on its knees battling for survival, and firefighters, police officers and teachers struggling to operate under crippling austerity cuts, whipping Tories into voting for such a costly, environmentally and economically detrimental project may come back to bite the Conservatives – and Britain – in a big way.