Using increased rates of Air Passenger Duty has been investigated as a way of forcing some flights to move away from the two airports as Heathrow is full and Gatwick will be in six years.
HM Revenue & Customs examined what would happen if passengers flying from Heathrow were charged a premium which would see them paying 50 per cent more in tax than at other airports adding, for example, £32.50 to the cost of an economy class flight to New York.