London does not serve England, it serves NW Europe. A larger Thames site (4 international runways and 2 domestic runways), and a 24hr operation, can provide routes to all of Europe - which LHR cannot do at present.
Since when are runways designated according to the traffic they serve - that is a matter for the terminals, or zones within them. To suggest such a use of runways really reveals a complete lack of knowledge of how the industry works. And you keep asking for data on fog?
Also, London already does serve Europe very well, but not every city through LHR as would be ideal, if the space was there. Last time I counted, every country in Europe that had at least one commercial airport had a link to London - except for Bosnia-Hg and Wales (if that counts!).
Some airlines have to make do with LGW or STN, but LHR still has tremendous frequency on many routes.
This larger airport will also provide easier links for regional passengers to fly in and interline out to the world. At present you are limited in carriers into LHR
Not really,
most of the major interline players operate through LHR, the other airports take more point to point - alhough yes, there are several players at LGW who would rather be at LHR, and some LGW BA destinations which also might otherwise be at LHR, BUT.....
And the eastern location of a Thames airport, will also allow easy TGV routes into Europe.
Again, I'm getting you on a technicality, but it shows your lack of knowledge. The TGV does not, and cannot operate through the Channel Tunnel, due to voltage issues. CDG is a rail transfer hub because it has fast, direct links to many other cities, but also because it is a stop on routes, such as between Lille and Lyon. For services through the Channel Tunnel to be viable, they have to be able to buy the track paths, and this is easier to pay for when you have 400m long trains, but they would be hard to fill on a spur into this new airport, not to mention that given the current tax regime, flights from Thames Island would be less competitive than CDG or AMS - but by the time it was built, that may change.
And why not leave a Cross-rail station and car-park on the old LHR site, to whisk you straight to the Thames terminals?
Because Crossrail is already likely to be extremely busy by the time it opens. It makes no sense to load so much extra traffic onto London's congested rail network by sending so many people from west to east.
And that, I'm afraid is the biggest problem with the new airport - build this amazing feat of engineering and architecture, if you can get the funding AND the planning approval (I doubt it could get either), but it could only ever work commercially if LHR closed, and the displacement of so many people would not be met by a commensurate upgrade of the surface infrastructure.
Just look at the fantastic Denver Airport, still not due to get its rail link until 2015.