Have ministers landed on Heathrow airport expansion?

A key Conservative election manifesto pledge opposing the expansion of Heathrow airport could be broken, BBC Newsnight understands.

Ahead of Tuesday's interim report into options for expanding capacity in the south-east of England, the programme understands that three of the favoured options include the construction of at least one new runway at Heathrow.

That could cause problems between Prime Minister David Cameron and some of his own MPs.

David Grossman looks at the options in the running and Conservative MP for Richmond Park and North Kingston Zac Goldsmith explains why a "U-turn" over Heathrow by the prime minister would be "catastrophic" and "an off-the-scale betrayal".