David Cameron delayed once again the decision he has been putting off for more than three years: whether to allow another runway at Heathrow Airport, and in so doing break a promise he made in 2010.

The prime minister swerved the decision in 2012 by asking Howard Davies to investigate the options for expanding airport capacity in southeast England, and ordering him not to report back until after the 2015 general election. Davies recommended expanding Heathrow to the west of London, while leaving open the option of an additional runway at Gatwick, to the south. Cameron responded late on Thursday by ordering a delay until after another election — the May 2016 contest for London Mayor.

The reason given for further months of uncertainty was the need for more research into the environmental impacts of expansion — something Davies dealt with in his report. The move was attacked by industry groups and Willie Walsh, chief executive officer of International Consolidated Airlines Group, which runs British Airways.

“To further delay a decision shows what we have repeatedly said — that party politics takes precedence over what is best for the economy,” Walsh said in an e-mailed statement.

The statement announcing the delay said that the further work would be done “quickly” and completed “over the summer.”

More Work

“The case for aviation expansion is clear – but it’s vitally important we get the decision right so that it will benefit generations to come,” Transport Secretary Patrick McLoughlin said in an e-mailed statement. “We will undertake more work on environmental impacts, including air quality, noise and carbon.”

A decision to expand Heathrow before the mayoral contest would have been a blight on Conservative candidate Zac Goldsmith’s campaign.

Goldsmith has pledged to resign as a lawmaker for Richmond Park, under the Heathrow flightpath, if the airport is expanded, and Cameron’s own reputation is also at stake. Before becoming prime minister, he gave a “no ifs, no buts” promise that there wouldn’t be a third runway at Heathrow, Europe’s biggest hub, and sponsored a tree in a protest orchard planted by Greenpeace at the site.

Johnson Plea

Cameron has had to weigh the competing claims of business groups and members of Parliament from outside the capital, who are pressing for extra capacity at Heathrow, and those of his party’s lawmakers from the west of London, who were elected on a platform of opposing the airport’s expansion. International Development Secretary Justine Greening, who represents Putney, and London Mayor Boris Johnson, who holds the seat of Uxbridge, have joined Goldsmith as vocal critics of the plans.

Johnson said in a statement the obstacles to expanding Heathrow are “insurmountable” and urged the government to look against at his proposal for a new four-runway hub to the east of the capital.

“To get to that position we need the government definitively to rule out Heathrow expansion,” he said in a statement. “ I believe that today’s announcement makes that much more likely.”

‘Gutless’ Decision

British Chambers of Commerce Director General John Longworth described the delay as “gutless.” Simon Walker, director general of the Institute of Directors, said business leaders “will be tearing their hair out” at the news.

“We have to ask now, what was the point of the commission if the government still fails to act,” he said. “At this stage, IoD members care much more about a decision being made than whether the new runway is built at Heathrow or Gatwick.”

In broadcast comments, McLoughlin said both London airports remain options.

“I am confident we can meet tough environmental standards,” Heathrow Airport Chief Executive Officer John Holland-Kaye said in a statement. An expanded Heathrow would link the U.K. to 40 new long-haul destinations such as Osaka, Japan and Panama city, the airport said, adding that it would work with the government to deliver hub capacity.

“This is a defining moment in the expansion debate,” Gatwick CEO Stewart Wingate said in a statement. “Expansion at Gatwick would give the country the economic benefit it needs at a dramatically lower environmental cost.”

–With assistance from Thomas Penny.

This article was written by Robert Hutton and Kari Lundgren from Bloomberg and was legally licensed through the NewsCred publisher network.

Photo Credit: British Prime Minister David Cameron speaks during a press conference. Ali Keplicz / Associated Press