Correct me if Im wrong, but latest figures suggest that a third runway and sixth terminal at LHR will cost something like £9bn, which will mostly be funded by BAA and the airlines i.e. NOT the taxpayer.
Boris island will cost upwards of £50bn, funded at least in a sizeable part by the taxpayer.
Surely the only thing that a third runway needs is political will to give it the go ahead, whereas Boris island needs political go ahead AND a large chunk of taxpayers cash?!
Let the taxpayer focus on HS2 (and link it to LHR!!!) and just give BAA the go ahead to build runway 3 and terminal 6