Heathrow Airport's controversial third runway could be blocked by environmental concerns, according to the Prime Minister.
Boris Johnson vowed to 'lie down' in front of the bulldozers when he was elected MP for the west London constituency of Uxbridge & South Ruislip in 2015.
The Prime Minister told ITV News he still opposed a third runway and said airport bosses had yet to show the runway would comply with noise and pollution curbs.
Asked if it was possible the third runway might not happen, Mr Johnson replied 'indeed'.
Look at what our manifesto says. It's very clear that Heathrow is a private sector project that has yet to satisfy very exacting legal obligations both on noise quality and on air pollution. The legal obstacles it faces in my view are still challenging. My position on it has been well known. Parliament voted for it but my position remains unchanged.