The government has said it will consider plans for a Thames Estuary Airport
I remain unconvinced for all the obvious reasons - it will be too costly, too risky, and it will alter London's geography too much. It is was replacing one airport, like Foster has done in Hong Kong, then the case might work out, but when London already has so many airport, investing in one super-hub seems unlikely to be able to pay its way.
That is why I think an extra runway at Gatwick is inherently more sensible, even if it isn't such a headline grabbing prestige project.
I've outlined my arguments in favour of Gatwick here.
Update 18th January
The government has announced today that they will begin yet another consultation on these proposals, after they were firmly rejected in the 2003 'Future of Aviation' White Paper. So what has happened to the industry since then?
Essentially, project demand for flights looks a lot less steep than it did then, not so much because of economic challenges, but because of the rising cost of oil - something many commentators, including myself - pointed out at the time.
Predicting demand over a 30 year period is still a risky business as there are so many variables - but the likelihood is that London may benefit from one extra runway. It is highly unlikely that such a vast new airport could pay for itself.
If, however, this project is taken seriously, then it is time for the engineers of HS2 to get their protractors out and rotate plans for the new Euston through 90 degrees. There is going to be a huge need for rail access to this airport, and this is likely to use the HS1 route and its connection to the new lines.