Courtesy Foster and Partners

Dubbed Boris Island, for leading booster London Mayor Boris Johnson, the Thames Estuary Scheme would require and investment of $200 billion by 2030, according to the airports commission.

An influential U.K. government commission on Sept. 2 excluded a vast scheme for a new four-runway hub airport in the Thames Estuary east of London from a shortlist of options to raise aviation capacity in southeast England.

London Mayor Boris Johnson, the estuary airport’s biggest cheerleader, has vowed to continue championing the plan. The commission will now focus on three remaining options that involve expansion of London’s existing Heathrow and Gatwick airports. The report is expected in the second half of next year.

Delivering and operating a hub airport in the estuary raised serious difficulties, reports Howard Davies, chairman of the Airports Commission, set up in 2012 to review short- to long-term options for the London region.

“The economic disruption would be huge and there are environmental hurdles which it may prove impossible, or very time-consuming to surmount,” he adds.

By ruling out an estuary option, the Commission is becoming irrelevant since expanding Heathrow would be politically impossible, according to Johnson.

The government has previously ruled out a third Heathrow runway. “In one myopic stroke, the Airports Commission has set the debate back by half a century,” he adds.

Sir Norman Foster, the architect who conceived the airport scheme based on the Isle Grain, says expanding Heathrow would be “a short-term fix." He criticizes the Commission for not pursuing further studies into an estuary option. “The pattern of the most competitive emerging economies is to replace the old and obsolescent and go boldly forward with the new, an opportunity today’s decision denies this country,” he adds.

The proposed four-runway airport known as “Boris Island,” would require major land reclamation in the environmentally important estuary, as well as new road and rail connections into the London area about 55 km away. It would require the closure of Heathrow, one of the world’s busiest international airports.

According to the commission, an estuary project would require investment of up to $200 billion by 2030, including the purchase cost of Heathrow and some $70 billion for transportation links.

Both Foster and the Johnson claim the costs are overstated.