By Laura Kuenssberg
It is the most eagerly anticipated "decision" in Westminster for quite some time. Except when the metaphorical white smoke drifts up over SW1 the likely outcome is that the "decision" is not to make a decision yet at all.
The politics of making a decision on building more runways in the South East of England were always going to be fraught - this time there's the London Mayoral election and a wannabe Tory Mayor, Zac Goldsmith who says he'll walk if Heathrow goes ahead.
There are strong arguments put forward by Gatwick's supporters, concerns over air quality at the West London option, and the implacable opposition from several members of the Cabinet.
By delaying, the government avoids a short term political problem and a pretty acute one at that.
