I don't think that anyone is in ANY doubt that the announced STN strip is the next for service. But, eventually, a politician will have to be prepared to make themself unpopular and talk about LHR and the satellite operation of EGWU is one possibility that sits to be taken.
Although traffic is already heavy in the area, do consider that on it's doorstep it has the A40 in dual carriageway and a Tube station.
When a new underground access is provided for the LHR Express, thy can dig a tunnel across to the tube with two travelators in it, as is done for LHR Central to T1/2/3.
Some expansion is required, some housing may have to go BUT the amount that has to go will be considerably less than any expansion of LHR main.
By the way - C17 dropping at 15,000 feet per MIN? That would sort out which pax had not yet secured their seat belt!
