LONDON — The British government has approved the construction of a third runway at Heathrow Airport, a decision that puts the long-running issue to an uncertain parliamentary vote.

Transport Secretary Chris Grayling described the decision by a Cabinet sub-committee as the right move for the country and one that signalled a commitment to global connectivity, which would boost the economy for generations to come.

“My department has met with local residents and fully understands their strength of feeling but this is a decision taken in the national interest and based on detailed evidence,” he said.

The location of a new runway in southeastern England has been debated for years amid concerns over pollution, traffic and noise.

The Department for Transportation last year asked the public for comments on the plans to build the runway at Heathrow, arguing the project would permit an additional 260,000 flights a year and give a 74 billion-pound ($99 billion) boost to the British economy over 60 years.

Heathrow is already one of the world’s largest airports, but the decision on whether to expand it has been a source of contention, particularly in Prime Minister Theresa May’s government.

Foreign Secretary Boris Johnson, whose constituency is heavily affected by the noise and pollution, once promised to lie down in front of bulldozers rather than allow the airport to expand. May’s constituency of Maidenhead, west of London, will also likely be affected by a third runway.

Greyling pledged lawmakers would vote by early July. Given that a number of lawmakers of the minority Conservative government have said they will vote against, May will likely have to rely on the votes of the opposition.

And even if approval is granted, the argument is likely to go on as a court challenge from anti-expansion activists is anticipated.

John Stewart, the chairman of the anti-Heathrow expansion group, Hacan, described the vote as a bad day for residents.

“Many communities will face a tsunami of noise if a third runway goes ahead,” he said. “Many people who will be under new flights paths will find their lives changed forever.”