Labour leaders could vote against allowing a third runway to be built at Heathrow due to environmental concerns about pollution.
The government wants to go ahead with Heathrow expansion but a final vote will not be taken in the House of Commons until 2018.
Labour has acknowledged the need for extra runway capacity in the south-east but has raised questions about the potential pollution and reduction in air quality created by Heathrow expansion.
Party sources have told the Financial Times that Labour leader Jeremy Corbyn is likely to vote against Heathrow expansion. Shadow chancellor John McDonnell is also an opponent of a third runway.
One Labour source told the FT: "It has to pass our tests and no one here expects that to be likely”; while another said: “If the vote is any time soon there is no way we would back it, mainly on the basis of air quality, and that’s unlikely to change any time soon."
Labour could turn against Heathrow expansion | Buying Business Travel