Boris Johnson can protest Heathrow expansion if third runway gets green light

The government will unveil its decision over whether to expand Heathrow Airport next week, Downing Street revealed this afternoon (18 October). Number 10 explained a cabinet sub-committee will decide whether a third runway gets the green light or not.

Conservative ministers opposed to Heathrow expansion, including Foreign Secretary Boris Johnson and Education Secretary Justine Greening, will be allowed to express "personal views" over the issue for a limited time. Ministers are usually expected to maintain cabinet collective responsibility.

Labour leader Jeremy Corbyn and Shadow Chancellor John McDonnell are opposed to another runway at Heathrow.

But Shadow Transport Secretary Andy McDonald told The Guardian the "imperative was overwhelming" for more capacity, implying he would back a Heathrow expansion over a new runway at Gatwick Airport.

Labour's Mayor of London Sadiq Khan favours Gatwick.

A decision to give Heathrow the go ahead could trigger a by-election. Former Mayor of London candidate and Conservative Richmond Park MP Zac Goldsmith has promised to quit over such a move.

He holds a majority of more than 23,000 votes over the Liberal Democrats, but the Old Etonian could run as an independent candidate.

"Uniquely he has the means to run as an independent. He is able to spend quite a lot on his campaigns," a Tory MP told The Huffington Post.