Time for a new airport for London?

Honestly, Lord Foster's shiny new T5 has yet to opened to the public and already people are sniping that Heathrow is too small. The leader/editorial in today's [London] Times calls for a new aiport to be built out in the Thames Estuary.

"Most countries have built new airports well away from the cities they serve. Heathrow, the world’s busiest international airport, grew out of an old RAF fighter station, not careful planning." There is, it opines, a simple and affordable solution: "A new airport could be built on artificial islands in the Thames estuary, away from the overcrowded city but close enough to be served by fast transport links." Airport nuts will say we've heard it all before. A Thames Estuary airport was planned from the 1960's onwards, but shelved in the 1970s, by the Tories.