From today's (17th 0ct) London Evening Standard editorial re: Gatwick expansion,
"Indeed, a new hub in the east is looking increasingly attractive as a long term solution. The Mayor's favourite Thames Estuary option would create fewer problems for densely populated areas than expansion at Heathrow, for instance. It would also meet the gradual shifting of gravity in the capital eastwards, something that the completion of Crossrail will expedite."
Sounds very similar to a certain PPRuNer!
Now, this isn't my opinion by any stretch, as I'm fully aware of the business case for 1 or 2 runways at Heathrow & maybe a 2nd at Gatwick in addition to that, but I reckon the government will actually only ever look at two options: Silver/Boris Island or Stanstead (That's for you Silver!)