As a Heathrow Resident (5 miles East of airport) and aviation enthusiast I feel this is yet another example of the authorities fudging the issue.....
Heathrow is unfortunately saturated (most of the day). They did 1300+ movements in a day last week for the first time ever. It is physically constrained and does not have very good communications links. There are also some serious safety risks due to the density of population around the airport.
It also has a massive impact on the local economy (positive) and the environment ( negative)
Terminal 5 was "sold" to the inquiry and local residents on the basis of no additional runway and no increase in flight numbers. BUT then we hear about a new runway and the stealth increase of daily movements through new operating and ATC procedures (and this does lead to more noise, more polution, more traffic etc etc).
Lets face the simple fact that SE England needs a planned mega airport like Hong Kong. Positioned suitably for access to London (where circa 50% of users need to travel) and integrated into a suitable transport infrastructure.
If only we had had the courage to do Maplin Sands in the 70's!