Ok cat among the pigeons time. I have always considered that LHR should be the only gateway. However my thoughts are changing and maybe there should be a more pragmatic approach to this. Here goes and ready to duck.
In my mind this could be a three stage solution as outlined below.
Stage 1, Open Northolt asap for limited regional flights a percentage of which must be transferred from LHR. Provide a fast coach link with connections to mainline/underground. This would be a temporary situation for a short period whilst......
Stage 2, A third runway is built North West of LHR with a life span of say 20 years.
Stage 3, Build Isle of Grain International to be completed before the expiry of stage 2.
This would allow expansion of our major hub in the short to medium term. Allow for the planning and building of Grain land and allow business and transport links to be integrated. Just think a loop off HS1 with international station that could be connected with HS2 by a sort tunnel between Euston and St Pancras. Crossrail also extended and a loop off the M25 and M2. Part of Heathrow would then close and be redeveloped say leaving one runway and terminal to just serve limited regional and international services for west London etc. You could also included a deepwater port a truly major transport hub.
Off to my bunker.
XT