A vote on expanding London Heathrow airport would win the backing of about 600 of Britain’s 650 lawmakers, a senior member of Prime Minister David Cameron’s Conservative party said.

Construction of a third runway at Europe’s busiest hub would secure overwhelming support if it was put to Parliament before Christmas, Graham Brady, chairman of the 1922 Committee of Tory backbenchers, said Tuesday in London.

“It’s a dangerous prediction but I think it’s about right,” Brady said in an interview after speaking in favor of Heathrow’s expansion at an event arranged by the airport’s operator. The opposition Labour Party, the Scottish National Party and the bulk of Tories all back the plan, he said.

Some prominent Conservatives, including London Mayor Boris Johnson, remain vehemently opposed to growth at Heathrow citing concerns over noise and pollution.

While Johnson has said he wouldn’t regard a government decision to go ahead with a new runway — recommended by a state-appointed Airports Commission — as cause to resign, London lawmaker Zack Goldsmith plans to force a by-election in his constituency over any such move.

“As with all of these things, we have to be sympathetic to local concerns,” Brady said. “But this is a national infrastructure project and most politicians recognize that. It’s a national decision.”

Cameron has said he’ll take a decision in the fall on whether to develop Heathrow into a 135 million-passenger-a-year superhub at a cost of 18 billion pounds ($28 billion).

This article was written by Christopher Jasper from Bloomberg and was legally licensed through the NewsCred publisher network.

Photo Credit: A sign protesting against a third runway is seen in the village of Sipson near Heathrow Airport in west London. Stefan Wermuth / Reuters