It probably has escaped most people's notice, but in last year's Budget it was announced that a new system of paying for APD ( Air Passenger Duty) would be introduced from November this year. The charge will then be based on the number of miles from London to your destination is in the World.
The U.S.A. and Canada for instance are in Band B and therefore the APD will increase from £40 to £45 in November and then to £60 in November 2010. Australia and New Zealand are in Band D so the charge to go there will increase from £40 to £55 then £85.
The increases are even higher in the premium classes such as World Traveller Plus, Premium Economy, or Business.