Skipless,
I beg to differ. Look at the area around LGW - significantly less populated than LHR, fewer people to object. Of course that doesn't mean it would get an easy ride, every airport has its anti-groups, and there is the wider green lobby to deal with.
Also, being purely cynical on the politics, the seats around LHR are more marginal, therefore MPs can see gain if they oppose its development. Much more blue around LGW. Now when it comes to HS2, yes there will be backlash from MPs on route (or not on route as case is here in Coventry), but it has cross party support. Therefore, if HS2 falls down, it will be due to its exorbitant cost per mile, and treasury re-evaluating case for it. If LGW is expanded using private funds, this is not an issue.
What is your solution to the problem? (Please don't say do nothing, there is an argument to be had saying the industry faces numerous challenges, but that is perhaps for another thread. For the purposes of this debate, we are assuming some level of growth, at least from Far East, so please include at least one new runway in your proposals).