I am firmly in the Heathrow expansion corner as it is the hub that is the most important factor for the benefit of UK plc. I also believe that the UK needs to think strategically for the longer term, something which the politicians have failed in for decades.
My plan therefore would be to:
1. Build a third runway at Heathrow asap, to serve domestic (poss UK + Ireland) traffic. As I understand it, LHR has about 480,000 movements pa of which ~66,000 are UK+I.
If these were moved to Rwy 3/T6, then all arrivals and departures would be from/to the north and not need to involve routine runway crossings and minimise SID/STAR conflicts.
66,000 movements pa equates to about 180 per day (90 dep + 90 arr) or about 12 per hour spread evenly over 15 hours, allowing for increased domestic routes if desired, achieving better access to the regions.
The capacity released would facilitate massive expansion worldwide using the present runways.
2. Recognising that LHR is not viable indefinitely, in parallel a longterm solution for a 4,5 or 6 runway replacement hub airport should begin in the Thames estuary or wherever. When it is finally built, LHR should be closed, as was Kai Tak.
What is most important is for the politicians to think beyond the next election for a change and come up with a strategy that is best for UK plc as a whole. But for me, to preserve any chance of maintaining our role as a major world hub, we need to build rwy 3 soonest.