LONDON — As any pilot will tell you, landing an aircraft in a crosswind is a challenge. So, too, is deciding on where — or whether — to build a new airport runway.
The political winds in Britain have shifted countless times over the decades on the question of expanding aviation capacity in and around London, which is already served by six commercial airports. No fewer than 10 government studies on the subject have been commissioned since 1946.
Conditions have grown particularly gusty lately as the government attempts to grapple with the airports question yet again amid ballooning budget deficits and an economy that has slid into a double-dip recession. The debate pits London’s business leaders, who argue that new runway capacity is vital for Britain’s global competitiveness, against environmentalists warning of the implications for the country’s carbon-emissions targets, and local residents who are already among the Europeans most affected by airport noise.
It also appears to have thrown a wedge into the fragile governing coalition of Conservatives and Liberal Democrats, who came to power in 2010 with a joint promise to reverse the course of the previous Labour government and block any expansion at London’s three-largest airports: Heathrow, Gatwick and Stansted.
Meanwhile, stark economic reality has begun to shake the support of the Conservative mayor of London, Boris Johnson — who is campaigning to be re-elected during a vote this week — for a bold, £50 billion, or $81 billion, project to replace Heathrow with a new airport hub.
“What has happened is we have now got the worst economic crisis in the postwar era,” said Simon Buck, chief executive of the British Air Transport Association, a trade group. “The government recognizes that it is vital for the economic recovery that we rebuild our international trade links.”
At the crux of the airport debate is Heathrow, Britain’s main international air hub, located to the west of the capital and, with more than 69 million passengers a year, the third-largest airport in the world, after Hartsfield-Jackson Atlanta and Beijing Capital International.
While it still serves significantly more passengers than any other airport in Europe, Heathrow, which has just two runways, has been operating at almost 100 percent capacity for a decade and been constrained from growing further by government indecision over whether to build a third runway.
Other major European airports, meanwhile, are catching up in terms of traffic: Charles de Gaulle Airport near Paris and Frankfurt International Airport, which each have four runways, last year had their passenger numbers rise 5 percent and 6.5 percent, respectively, while traffic at Amsterdam Schiphol, which has six runways, jumped more than 10 percent.
Those same airports are also expanding their connections to cities in the largest emerging markets in the world — including Brazil, Russia, India and China — where the International Monetary Fund predicts half of the global economic growth will take place over the next decade.
The absence of spare capacity at Heathrow means that it already has fewer weekly flights to those emerging countries. In 2011, for example, Heathrow offered 31 weekly nonstop flights to mainland China, while Amsterdam had 39, Frankfurt 56 and Paris 64.
Reports commissioned last year by Heathrow’s owner, BAA, estimate that Britain could miss out on roughly £14 billion in international trade over the next 10 years, while 141,000 jobs would be lost, if the airport continued with two runways.
“I am really worried this is another industry that Britain risks slipping from a position of great strength to one of mediocrity,” said Kwasi Kwarteng, a Conservative legislator and a transport committee member who supports building a third runway at Heathrow as the most economical near-term solution to the capacity problem. “In the face of a growing market, to say that we are not going to build anymore seems absolutely crazy.”
As Britain’s economic crisis deepens, political leaders who had fiercely opposed any new runways at London’s existing airports may now be softening their stance. An aviation strategy paper that Justine Greening, the Conservative transport minister, had been expected to publish at the end of March was abruptly postponed until the summer.
According to media reports, George Osborne, the Conservative chancellor of the Exchequer, said at a cabinet meeting in March that the government intended to include new runway construction among the options to be considered — to the fury of Nick Clegg, the Liberal Democrat deputy prime minister, who opposes any further airport expansion on environmental grounds. Britain has said the aviation sector’s carbon dioxide emissions by 2050 must not exceed 2005 levels of 37.5 million tons a year.
Representatives for Mr. Osborne and Mr. Clegg declined to comment on those reports and Ms. Greening, in a statement, said the government’s position against expansion at Heathrow “has not changed.”
That probably means the government will take a closer look at the case for expanding London’s other main airports — Gatwick, Stansted, or possibly Luton — with an eye to migrating some of Heathrow’s domestic and European flights there, analysts say. London City airport has not been considered an option for adding capacity because its urban location makes any significant expansion impractical. London Southend, a former military airport that re-opened for scheduled passenger flights in April, can be expected to accommodate no more than two million passengers a year by 2020, a tiny fraction of the nearly 134 million passengers who pass through all London area airports today.
But apart from such incremental solutions is a far more ambitious proposition by Norman Foster — the British architect whose firm, Foster + Partners, designed the new airports in Beijing and Hong Kong — to replace Heathrow with a new air and rail hub in the Thames River estuary, around 40 miles, or 25 kilometers, to the east of the capital.
Mr. Foster’s proposal is breathtaking in scale: A four-runway airport, to be built on reclaimed marshland, connected to London via high-speed rail, whose access tunnel would double as a flood protection barrier and hydropower generation plant.
A few years ago, the idea captured the imagination of at least one very influential advocate: Mr. Johnson, the London mayor, who lobbied hard to persuade aides to Prime Minister David Cameron to support the project.
“We should not be so short-sighted as to aim at catching up” with other European airports, said Hew Thomas, a partner in Mr. Foster’s firm. “What we should do is leapfrog.”
He added, “New jobs in intellectual services and other 21st-century sectors will not rely on Victorian-era steam engine infrastructure.”
Yet critics of the project, which some have mockingly dubbed “Boris Island,” abound. London First, an influential lobby representing 200 of the city’s largest employers, says that London cannot afford to wait the 20 to 30 years that a new hub would take to build.
While Mr. Foster argues that most of the £50 billion cost can be borne by private investors, including foreign sovereign wealth funds, many politicians on the left and the right expect that taxpayers would end up footing a sizable part of the bill.
Meanwhile, environmental campaigners, including Greenpeace, the World Wildlife Fund and the Royal Society for the Protection of Birds, oppose the destruction of protected estuary habitat for up to 500,000 migratory birds, many of them endangered.
Even the biggest player in British aviation remains unconvinced of the feasibility of an all-new hub to replace Heathrow.
“I give credit to the mayor of London,” said Willie Walsh, chief executive of International Airlines Group, the parent company of British Airways, which is based at Heathrow. “At least he’s thinking big. At least he’s getting the question discussed. But this is an idea whose time never seems to come.”
Among the questions that Mr. Walsh and others say remain unanswered is how the economy of west London, an influential political constituency, would cope with the closure of Heathrow and the loss of up to 200,000 jobs.
“If a Thames airport were built, it would have a significant and devastating impact on the west London economy,” acknowledged John Stewart, chairman of Hacan ClearSkies, a group representing west London residents opposed to an expansion of Heathrow.
“Heathrow is almost too big to fail,” Mr. Stewart said. “I can’t foresee any government actually closing it down. You can argue that it’s in the wrong place, that it causes tremendous noise problems, which are all true. But equally, in the real world, we are stuck with it.”
Mr. Johnson, having perhaps seen the political writing on the wall, has grown noticeably less vocal on the airports issue in the run-up to London’s elections. Neither the mayor nor his aides agreed to be interviewed for this article. But in a telling quip to The Independent on Sunday recently, he said: “Contrary to popular belief, I am not the slightest bit wedded to some remote archipelago in the Thames estuary.”
By ruling out expansion at Heathrow in 2010 and failing to back Mr. Johnson’s Thames project, some observers said the coalition government had backed itself into a corner.
“It was very much a political decision to rule out the new runways,” said Mr. Buck of the British Air Transport Association. “Now they are under intense pressure from a number of their own supporters and an increasing number of business people to do something to ensure we maintain good trading routes so that future economic growth doesn’t end up going elsewhere in Europe.”
The government has set itself a deadline of next year to agree on a way forward. But given the extent of the current political paralysis, analysts said they were keeping their expectations low until at least the next general election in 2015.
“There is no reason to think any clear definitive solution will be happening anytime within the current government and probably next five years,” said David Feldman, managing partner at Exambela, an aviation consulting firm based in Paris. “This is not a decision for the current government, but probably for three governments from now.”
By that time, according to Mr. Feldman, London may well be on its way to becoming a second-tier hub for air travel.