I'm from Ireland so I dont know who's in charge of Heathrow/Gatwick/Stansted but I wish whoever is on charge would stop talking about all the long term risks/negatives/problems associated with a 3rd runway. We've heard it all before ! Hurry up and do something quickly !
I think the ideal solution is a 3rd and 4th runway and a terminal 6 at Heathrow, 2nd runway at Gatwick and Stansted. No new estuary airport, it will take too long & has as much negatives about it as expansion at Heathrow. I know my idea is a bit... Far fetched but I think this will facilate the aviation needs for London for decades to come. Look at markets where London missing out on (Osaka, big cites in China, Santiago)