High Quality Content by WIKIPEDIA articles! A new Thames Estuary Airport has been proposed at various times since the 1970s. London`s existing principal airports, Heathrow, Gatwick and Stansted, are all situated in locations that are sub-optimal in various ways, such as being too close to built-up areas or requiring aircraft to fly low over London. In the case of Heathrow the growth of air traffic has meant that the airport is close to capacity and any further expansion would require the demolition of substantial parts of West London and an increase in noise and atmospheric pollution across the whole city. Several locations for a new airport have been proposed in the Thames Estuary, to the east of London. These have included Maplin Sands, Foulness on the north side of the estuary; Cliffe, Kent and the Isle of Grain on the south side; and artificial islands located off the Isle of Sheppey such as the "Boris Island" proposal championed by Boris Johnson, the Mayor of London. However, none of these proposals has been implemented. Economic considerations have so far ruled out a new coastal airport while political considerations have ruled out a new inland airport, leaving planners with an as-yet-unresolved dilemma.