An old adage holds that one gets only a single shot at a first impression, and rarely is this as true as in the realm of international travel. For better or for worse, foreign visitors’ initial view of Britain is London's Heathrow Airport, and the impression left is often closer to worse than it is to better.

By number of international passengers, Heathrow is the world’s busiest air terminal. Operating at 99 percent capacity, it cannot get much busier. Heathrow is also the least punctual airport in the United Kingdom: 27 percent of all air traffic is delayed by fifteen minutes or more, and in the last year the average delay has increased from two to fourteen minutes. In a review of the top ten British airports, Heathrow came last.

That the airport is saturated despite the downturn in air traffic ushered in by the global recession gives an indication of future trends. It was with this in mind that, in 2009, the Labour government greenlit an expansion and signed off on a long-desired third runway.

Unfortunately, the euphoria of expansion was short-lived. Upon coming to power in 2010, the Conservative Party followed through on a popular campaign promise and, in concert with the vehemently anti-expansion Liberal Democrats who form the other half of the ill-suited coalition, it killed the project. Landing gear up!

Americans who would assume that the Conservative Party was an instinctively prodevelopment outfit should be forgiven for their confusion. This is not the case. British conservatism is by no means the same as American conservatism; British conservative voters often live up to their names, tending toward parochialism and reaction. This tendency is in part the product of a desire to maintain the value of their (typically rural) property by opposing any development that might drive down prices or ruin the views. It is also the product of an instinctive opposition to economic change, a position that has no real counterpart in U.S. politics.

Most recently, advocates of a third runway have been buoyed. In September, the prime minister sacked a strongly anti-expansion transport minister and announced a new commission on the third runway. The coincidence convinced some observers that the government is in the process of changing its mind or, at the very least, moving out of its holding pattern. Now there are rumors that George Osborne, the progrowth chancellor of the exchequer and Prime Minister David Cameron’s right-hand man, is in favor of the development and has been exerting pressure on his boss.

If the speculation is true, the chancellor is an outlier. Conservatives routinely have been vocal in their opposition to a third runway. Popular London mayor Boris Johnson described the proposal as “mad” and pledged to lead a fight should the government change its mind. Former Ecologist editor and conservative member of parliament Zac Goldsmith—whose youth and environmental credentials helped to convince the public that the Conservative Party had changed into a more “compassionate” and environmentally conscious form—wrote recently in the Guardian that a government U-turn on the issue would be “deeply unfair” and an “off-the-scale betrayal.” This sounds rather hyperbolic to foreign ears, but he has a majority of the public and parliament behind him—and he knows it. Mayor Boris has a good ear for populism, too.

Heathrow expansion advocates within the Conservative Party such as Osborne not only have their members to contend with but also are fenced in by their coalition with the left-of-center Liberal Democrats. The Lib Dems, a perennial third party that the coalition has afforded a rare position of influence, have insisted that there will be no third runway at Heathrow while they remain part of the government. This will make progress intensely difficult and almost certainly will prevent the development being presented by the prime minister as a fait accompli. The Lib Dems are already in trouble with their own base for having caved on university tuition fees—which were raised despite their promise to block any such move—and can ill afford another public loss. Expect them to hold the line on the Heathrow issue as if their future depended on it. And it might well, given how many appear to be defecting to Labour.

The battle lines are thus drawn, and war makes odd bedfellows. In the corner of economic growth, increased business investment, construction jobs, ensuring competitiveness and expanding air capacity are the business groups, the British Chamber of Commerce and the Confederation of British Industry, as well as the big labor group, the Trade Union Congress. Not your normal allies, to say the least. On the other side are all three major British political parties and a panoply of environmental groups opposed to the expansion of air travel on principle. The celebrities have pitched in, too. On behalf of Greenpeace, the actress Emma Thompson bought a piece of land on the proposed site from which to mount legal challenges and slow down construction.

The anti-expansion groups oppose the various aims of the third runway: they do not care if airport business going to rival European nations because they wish to decrease overall air traffic; they do not mind that Heathrow is at full capacity, as this helps to limit global warming and aircraft noise; and they are not concerned about the loss of investment at the local level, because development would mean that seven hundred homes—some of them historically protected—would have to be demolished.

Some savvy environmentalists have taken to pretending that, as an alternative, they are fine with the country’s regional airports picking up the overflow. This is a red herring, and they know it. It is simply impractical for a capital-centric country like Britain to expect that most foreign travelers want to fly into Manchester, Birmingham or, worse, the shabby suburban terminal in Luton. The government also has prohibited expansion of London’s two other airports, Stansted and Gatwick. Thus, Britain is the only advanced economy in the world whose leadership is fighting plans to expand its air routes.

As it stands, Britain trades more with little Ireland than it does with expanding China. While France and Germany have taken concrete steps to ensure that emerging markets have access to their economies, the British are pussyfooting around—behaving like Little Englanders. Now is not the time to equivocate but instead to ensure that, as Britannia once ruled the waves, she has a fighting chance in the skies as well. “Still more majestic shalt thou rise,” read the words to the old song. Under current plans, we will do no such thing.

Charles C. W. Cooke is an editorial associate at National Review.