The plans have been drawn up in preparation for the decision next year on whether an estuary airport is feasible to replace Heathrow.

The designs for a new 'Heathrow City' have been commissioned by Transport for London and backed by Mayor Boris Johnson.

Mr Johnson, who wants a Thames Estuary hub airport, says the Heathrow redevelopment was needed given the demand for homes.

According to the BBC, one of the designing architects, Hawkins Brown, envisages a factory for self-build modular homes on the Heathrow site where people could order homes to their own specifications.

Another design from Rick Mather architects sees the  site becoming a new hub city by using the existing runways and terminals to define the structure of the city and connect 10 local centres.

Architects Maccreanor Lavington's vision for Heathrow City is  to "develop a fully functioning city within the capital" and large tracts of woodland would be planted.

Mr Johnson said: "The demand for new homes and jobs in the capital is such that we must be ready to start redeveloping Heathrow the moment it moves to its new site. And the sooner we start planning the better.

"However the key point is that all these scenarios would potentially create some of the many thousands of new jobs and homes this city will require given London is expected to increase in size by a fifth within the next 15 years."