A NEW airport just miles off the south Essex coast must be built to avoid “economic stagnation,” the Mayor of London has vowed.

The case for a Thames estuary airport has gathered pace as Boris Johnson told business leaders the project must become reality if the country is to stay an economic powerhouse.

If built, the new complex would be the biggest airport in the country. It is deemed necessary as airports in the South East are expected to be at full capacity by 2030.

Two proposals have been made public.

A blueprint for the Isle of Sheppey, nicknamed Boris Island, has been discussed since 2008 and earlier this month, renowned architect Lord Norman Foster revealed plans for the Isle of Grain.

Both schemes are estimated to cost more than £40billion. If either were to get the go-ahead, the new airport would be only a matter of miles off the coasts of Southend and Canvey.

Speaking at the Institute of Directors in London yesterday, Mr Johnson said a new airport was essential to ensure business leaders continue to fly to London in the future in order to do business here in the UK and not elsewhere.

He said: “There is no doubt to do nothing will lead to economic stagnation.

“The Government must now grasp the nettle and begin serious plans for the multi-runway solution that can keep London, and our great nation, in the premier league of the global economy.”