Boris Johnson today launched an eleventh hour bid to keep alive his plans for a four-runway airport in the Thames Estuary.

Both Alex and I live in London and can witness the unfolding of this politically-sensitive saga with no end in sight.

Everyone agrees that London is falling behind other hubs in Europe. No one does when it comes to what should be done.

LHR is the current hub, but it's constrained by its inability to add a third runway (and the unwillingness of any government to confront this reality). 

LGW insists it should add a second runway—which, let's be honest, won't create a hub unless someone comes up with a high-speed rail solution with LHR.
So far though, the definition of "high speed train" in the UK is a joke compared to continental Europe, Japan or China. And many have doubts that a hub can truly be created by simply inter-connecting airports.

The Mayor of London pushes for an entirely new airport with 150m PAX capacity, far away from cities—solving the noise issue (but coming with its own environmental cost). Again, one can hope it comes with a truly high speed connection.
But more importantly, will the government have what it takes to invest that massive amount of money?

My favorite solution would be to move LHR's runways westwards, over the current water reservoirs, but I fear that is not in the cards anymore.