24 hour ops over London - never going to happen.
Labour will approve the 3rd runway (they need all the plus points rom business they can get at the moment) but it will only get pulled after the next election.
LHR could, theoretically, be given government approval for a 3rd runway tomorrow. LGW has a longstanding agreement which forbids expansion for another 11 years. The two are not remotely similar.
2nd runway from Gastwick can operate from 2019, planned opening date of runway 3 at LHR is 2019/2020 - more or less the same
LGW has a large town to the south, residential areas to the north, and a motorway to the east. I agree that putting another runway in there, post-2019, would be easier than LHR but no doubt it would still encounter a huge amount of anti-expansion protests.
Crawley is a couple of miles to the south but runways are East West. Going north you could go 12 miles up the M23 and over the M25 before you land on someones house - make a heck of a single runway. I would suspect looking at a map 3 additional runways E/w could be put down and at least 1 N/South and barely touch anyones property and not overfly crowded areas anything like the same extent now.
Wont the need for expansion be rendered academic anyway if the era of cheap flight is over?