Boris isn't letting go, is he? He and a bunch of other Thames Estuary airport campaigners nipped out on a dredger on Friday to inspect the likely site for this blue-sky-thinking aviation hub. The result? Boris and Doug Oakervee, the man behind the feasibility plans, are more enthusiastic than ever.
We've also now got more detail about the Mayor's vision. Marinair would have four runways, split across two islands, and linked up to Crossrail and the high-speed European network so passengers could take the train for connections to the continent. Underwater turbines would generate its electricity and planes would take off and land over open water, apparently minimising disruption to residents in Essex and Kent.
It might sound fantastical but Oakervee is the man behind Hong Kong's island airport, so he knows what he's talking about. Could this be a realistic option rather than a harum scarum scheme?
Well. If environmental concerns are huge at Heathrow, they'd be even bigger at the Thames Estuary. The area is protected by international law and, despite assurances that planes wouldn't be taking off over the mud flats, we've seen enough of what our bird friends can do to be a bit, um, nervous. Plus it'd cost £40b to build, the new homes for its workers would be constructed on flood plains and oh-so-many other hassles.
(Boris also confirmed he'll launch a legal challenge to Heathrow's third runway, which is scheduled to concrete over Harmondsworth and Sipson, within weeks. It'll be a popular move; figures from the Department for Transport last week revealed an enormous anti-expansion response to their consultation. We guess the government just put its hands over its ears and sang 'we can't hear you'.)
An Estuary airport would be an amazing feat if it could be pulled off. In some form that would protect wildlife and not bring down planes every migration season. But, y'know, if we can manage the Olympics... hey, we said if.