A proposal to construct an airport in the Thames Estuary has won the political support of the Prime Minister, senior cabinet members and the Treasury.

The Daily Mail reports that the proposed airport could cost £40 billion - and could also replace Heathrow as the UK's largest airport. The new airport will have four runways.

The newspaper adds that a separate £50 billion Thames airport scheme has been drawn up by architect Lord Norman Foster, for the nearby Isle of Grain in Kent. Lord Foster designed the new Wembley stadium.

London Mayor Boris Johnson is expected to launch a policy paper on Nov. 21, calling for more runways to be built. All airports in the southeast are likely to be at full capacity by 2030, which has led to growing concern among policy makers about future flying facilities. The Department for Transport is due to produce a report on aviation in 2013.

Planes will probably fly in from the northeast, primarily over water and thereby greatly reducing the number of homes that would be affected by aircraft noise.

Although the planned airport has got the government's support, local opposition MPs, local officials and residents of that area are against any such construction.