Many visitors to London will be used to flying over the Thames before they land.

Within less than 10 years, they could be touching down at an island airport in the middle of the river itself.

A futuristic-looking, six-runway airport on an artificial island has been proposed at a location off the Isle of Sheppey, around 80 kilometers from the center of the city.

The plan from a consortium formed by the mayor of London, Boris Johnson, has been projected to cost £47 billion ($76 billion) and to take seven years.

With Heathrow running at 99% capacity, the capital needs more runways, the consortium, Testrad , says.

The mid-river location is intended to avoid adding to the aviation noise pollution already bedeviling London -- the source of long-running campaigns from residents beneath that approach into Heathrow that passengers so enjoy.

Trees growing in terminal

A visualization of the proposed London Britannia Airport shows an oval-shaped stucture bisected by runways, sitting in the Thames where the river widens to form an estuary.

Interlinked, translucent hemispherical pods cover the concourse and other passenger areas -- the light they admit allowing trees and other vegetation to grow within.

Heathrow Airport, currently the busiest in Europe by passenger traffic and the third busiest in the world, would close if Britannia Airport went ahead, Gensler, its designers, said.