LONDON

The British government Tuesday announced its support of the decision to expand the capacity of the Heathrow Airport with a third runway, drawing mixed criticism.

"This decision is a long overdue step in the right direction," Interim Chair of the National Infrastructure Commission, Lord Adonis, said in a statement in response.

“It has been clear for decades that the UK needs additional airport capacity in the South East to remain open and competitive on the world stage, yet for far too long political indecision has prevented this," he said.

London Mayor Sadiq Khan, a long opponent of expansion, said the government's decision to expand Heathrow was not only a "wrong decision" for London, but for all Britain, and would be "devastating for air quality" across the city.

"The government are running roughshod over Londoners' views – just five months ago I was elected as Mayor on a clear platform of opposing a new runway at Heathrow," Khan said in a statement, vowing to continue challenging this decision.

"I am exploring how I can best be involved in any legal process over the coming months," he said.

Conservative MP for Richmond Park and Kingston Zac Goldsmith is expected to resign in protest at the expansion in order to "honor his pledge." Richmond Park is just eight kilometers (four miles) from Heathrow.

"Following the Government's catastrophic Heathrow announcement, I will be meeting my constituents later today (Tuesday) before making a statement," Goldsmith tweeted.

Foreign Secretary Boris Johnson who is also among the opposition had vowed to lie down in front of bulldozers if a third runway at Heathrow was approved.

Commenting on the decision in the House of Commons, he said a third runway was "undeliverable."

"I think it very likely it will be stopped," he said.

Heathrow is the UK’s largest airport which operates 1,300 take-offs and landings every day of the year, and successive British governments have equivocated over the question of airport expansion around London since 2006.

Heathrow has two runways that are practically filled to capacity and the airport has been losing ground to its rivals. In 2014, it lost its mantle as the world’s busiest international airport to Dubai.