Heathrow Airport would cease to exist and a new London borough would be created in its place, under the ambitious London Britannia Airport plans endorsed by Mayor Boris Johnson.

The Thames Estuary Research and Development company (Testrad) has unveiled designs for a brand new, six-runway airport on the Thames, to the east of London, and say it could be built in just seven years.

Hinting that Heathrow would not survive if a new hub airport was built, Testrad say that the £47billion cost of the new airport would be covered by "recycling" Heathrow land, and building a new borough from scratch.

A London Borough of Heathrow would be a city extension for London, provide 300,000 new homes and 200,000 jobs, and be "a technopolis centre for regional high technology enterprise," says the consortium.

A high-speed rail link from the new airport to the borough is also proposed.

Mr Johnson, who has long championed the London Britannia Airport vision, formerly dubbed "Boris Island", said at the Confederation of British Industry (CBI) conference last week that third runway plans were "toxic" and "politically...undeliverable."

The Airports Commission, tasked by the government to recommend the best way to deliver extra runways in the south east, will reveal a shortlist of the most viable options next month.

Heathrow has put three third runway locations forward, which would decimate Harlington, Sipson, and Stanwell, but insist that it could be built at a fraction of the cost of a new Thames Estuary hub.

Do you think the London Britannia Airport is a good idea? Could the Heathrow Borough vision be realised? Could London Britannia and Heathrow Airports co-exist? Leave a comment below, or email jack.griffith@trinitymirror.com with your views.