Lord Foster's Thames Estuary airport plan 'pie-in-the-sky'
A plan for a four-runway airport in the Thames Estuary has been branded a "daft pie-in-the-sky" scheme.
The airport, which could be capable of handling 150m passengers a year, has been outlined by architect Lord Foster for the Isle of Grain in Kent.
The scheme, costing at least £50bn, would be built on partially reclaimed land and have high-speed rail links.
However, Medway Council said building it near existing gas terminals was a "potentially lethal mix".
In outlining the plan, Lord Foster said Britain needed a modern transport infrastructure.
The project, a rival to London Mayor Boris Johnson's own plan for a Thames Estuary airport, comes after a £100,000 study carried out by Lord Foster's firm and infrastructure consultants Halcrow.
"We need to recapture the foresight and political courage of our 19th Century forebears if we are to establish a modern transport and energy infrastructure in Britain for this century and beyond," he said.
"Britain can no longer trade on its inadequate and aged infrastructure."
The architect's previous projects include Honk Kong's Chek Lap Kok airport, which was also built on reclaimed land.
Each of the four runways would be 2.5 miles (4km) long, with planes approaching from the north east over water.
A railway station would be built under the airport.
The plan also includes a new Thames barrier to offer flood protection and generate carbon-free energy from the tide.
The scheme's unveiling comes a year after Prime Minister David Cameron told the House of Commons the government had ruled out a major airport in the estuary.
Medway Council denounced the Isle of Grain as one of the worst places anyone could build a new airport.
"The plan to build an airport on the Isle of Grain is, quite possibly, the daftest in a long list of pie-in-the-sky schemes," said leader Rodney Chambers.
"The Isle of Grain is home to one of the world's largest liquefied natural gas terminals.
"It is obvious that aircraft and huge gas containers are a potentially lethal mix.
"In addition to this, the sunken American warship the SS Richard Montgomery is submerged just a few miles from the location and laden with high explosives, the London Array wind farm is being built nearby and the airport cuts through an area that is home to hundreds of thousands of migrating birds."
Friends of the Earth said building the airport would have a "devastating impact" on wildlife.
Spokesman Paul de Zylva said: "[This would be] all for overhyped promises of economic benefits that have been proven to be false.
"The aviation industry has been selling our environment down the river for far too long - ministers must say 'no' to airport expansion and the climate devastation it would bring."