Surely it is time for an assessment of whether Heathrow is the best location for further development?
How do the location and transport links stand up (not to mention the ATC restrictions and overflying Central London) compared to major airports elsewhere (and I'm not restricting this to England or even the UK)?
Would doubling the passenger throughput of Heathrow resolve the current limitations (and could the infrastructure cope)?
RAF Lyneham and RAF Manston have been mentioned, and there were plans to build on the Thames Estuary (as well as other locations 'around' London).
Heathrow has established transport links, but these are shared with other traffic so congestion is endemic (and would increase with more passengers).
Given a clean sheet of paper (!) would Heathrow be the best choice for London Airport (and why do operators not simply move their operations elsewhere - to other so-called London Airports?)?
Could existing aviation sites be 'incorporated' into Heathrow (or other locations) and operated as satellite 'terminals' (I'm thinking of that place just north-north-east of Heathrow - Northolt) with rapid-transit links (as has been proposed for Gatwick)?