The reason the Government (tory and liberals) don't want Heathrow expansion is simple, votes! Politicians want one thing to get elected, and fulfill their ambition for power. They are not interested in the long term economy of the country, just getting elected! There are a lot of marginal constituencies around Heathrow, so if you tell the voters no 3rd runway vote for me........The fact that Frankfurt has 4 runways never mind 3 says it all. That's why U.K. is falling behind in terms of hub growth, and most other long term economic plans, because of useless politicians. So the jobs go elsewhere, they trash everything then blame something else e.g. last Government, global downturn etc etc.