Heathrow expansion is one key policy area that is affected by the recent Labour elections. Sadiq Khan’s victory in the London mayoral nomination contest means that the London Labour party will be campaigning against a third runway. Tessa Jowell was tentatively pro-Heathrow but Khan made a pledge during the campaign to oppose a third runway — one that he would find it very hard to renege on. And assuming the bookies are right and Zac Goldsmith is selected as the Conservative candidate, all of the London mayoral candidates will be campaigning against Heathrow expansion (the Greens and Lib Dems are also likely to be against it).
The Labour party overall is heading in an anti-Heathrow direction, thanks to the election of Jeremy Corbyn as leader. Labour had cautiously backed the Airports Commission's proposals but Corbyn told the Independent that a third runway would lead to ‘massive increases’ in air and noise pollution:
'We should be ensuring our existing national and regional airports are linked effectively by public transport and work together to maximise existing capacity and help spread economic benefits across the country'
The elevation of John McDonnell to the shadow cabinet essentially confirms that Labour will not back a Heathrow expansion. McDonnell, who represents a constituency in west London, has been a long time campaigner against a third runway — going as far as losing his temper during a Heathrow debate in 2009 and being suspended from the chamber for grabbing the mace:
Yet despite all of these personnel changes, Coffee House understands that pro-Heathrow campaigners are not too concerned about their cause, with sources pointing out that the situation has not really changed. The government has yet to formally back the Airport Commission’s proposals for a third runway but it is expected to and a vote in the Commons is expected in the near future.
Campaigners believe there is still a majority of MPs — including many moderates in Labour — who would vote for a third runway. There are plenty of Labour councillors and council leaders who are pro-Heathrow, as well as some major trade unions:
Regardless of whether Khan or Goldsmith wins the mayoralty next year, there is not much either candidate can practically do to stop a third runway beyond heckling from the side lines. In this respect, the mayor (if he isn't an MP) is essentially a very loud lobbyist. Boris has done that for the past few years and it appears to have made little practical difference.